I've had just about every position there is on the childcare ladder. From occasional babysitting to full-time nanny, each require a separate but occasionally overlapping set of skills, and must be compensated as such. Depending on your individuals family's needs, these may vary on a weekly, monthly, or yearly basis. So I figure I'd break it down in a way that hopefully is helpful when you're trying to figure out what works for you.
The language I am going to use also varies between individuals. Who one person calls a babysitter, another calls a nanny. The terms used can raise a lot of feelings about ethics, especially when hiring women of color, and I do have a lot of feelings about that, but perhaps will discuss them at another time. I understand why a woman would want to call someone who takes care of their child full-time a babysitter (as opposed to a nanny) because of weird class implications or white guilt, but to me, the word nanny implies someone who is helping in the raising your child, as opposed to a teen who orders pizza and plays some board games. So here we go!
This is someone who you can call when you have a date night, party to attend, need to get out of the house for a few hours, etc. A high school or college student with a flexible schedule and who doesn't need a lot of hours is perfect for this job, since they're hired by the hour. It's helpful to have more than one who you know and are comfortable with so you have a backup. Responsibilities include getting an easy dinner together, such as ordering out or unfreezing something in the oven, getting kids bathed and in bed, and tidying up the house of any toys played with or dishes that were dirtied.
A mother's helper entertains the children while the parent is at home. Typically a college or high school student, with a flexible schedule, but who works fairly regular hours in the home. This is what I did in college and how I got started working with infants. Typically, the mother would be home part- or full-time, so I would help with whatever she needed: watching the older children while she napped with the newborn, or helping to make meals, tidied the house, watched the baby while she took the older kids to school or practices, etc. There are more responsibilities, and the mother's helper can count on a fairly regular income.
Nannies actively help raise children and are an integral part in the day-to-day activities and family life. Responsible for driving or getting children to and from their activities, going through a daily routine, helping discipline when necessary; enforcing the values and rules that the parents have laid out for their families. Makes full meals, cleans up after the children, comfortable with bedtime and bath routine, entertains them, and has a knowledge of childcare techniques and extensive experience with children of all ages. Nannies should be compensated accordingly and have a set schedule.
An au pair is typically a student from a foreign country who helps out with the children while she continues her studies. She is given room, board, and a stipend in exchange for a set amount of hours of childcare. An au pair typically does not do housework, and most likely you will work with an agency when finding one so as to adhere to local immigration laws. I almost went to London as an au pair for the family of a rock star when I was like, 23 years old, but Lourdes decided she wanted to stay in Los Angeles and enjoy her early 20s with her friends. Like, if I told you who it was, you'd be like, WTF were you thinking!? I think it's easy in hindsight to say it was a mistake, but I would have given up a lot if I had left at that time, I think.
A nanny-share usually equals one nanny + two families. So the nanny either watches the kids from Family A 2.5 days a week and the kids from Family B the other 2.5 days. OR it means that the nanny watches the children from both families at the same time, at one of the families' homes. This option is usually cheaper for the parents and the nannies make significantly more money. Child-care swap involves two families with parents who alternate days to watch each others children in addition to their own. This arrangement is free and can be quite convenient if you have a friend or other family you are close to and with whom you have good communication.
(I am not going to discuss day care alternatives because, frankly, it's not something I am familiar with at all. I have always worked in private homes for individual families and have no experience in day cares, whether in a center or a residential home. This does not mean I am anti-daycare at all! I just have no personal experience with them!)
When hiring a childcare provider, it's important to ask as many questions as possible to help you feel comfortable with having this person in your home and caring for your child. Do not be afraid to ask about past experiences, how they discipline children, if they have a childcare philosophy, or if they smoke! You can also request that your childcare provider take a CPR/First Aid class, if they haven't in the past two years. Typically, you would pay for your childcare provider to take the class at a local community center or fire station.
I've had a lot of success finding families online, at Care.com and Sittercity, though I prefer the layout of Care and have had a bit more success with them. I would be wary of Craigslist, but to be perfectly honest, I found my travel nanny job there many years ago and it was amazing. That said, it was a long time ago and I definitely wouldn't do that again. You can also go through a professional agency; I worked with The Help Company in Los Angeles, and they placed me with a wonderful family that I am still close to.
There are a lot of childcare options out there, so take the time and find what is right for your family, you shouldn't have to compromise on quality care for your kids. There is something for everyone, just be clear with your intentions. I once had a family who hired me to babysit on the weekends, which was great, but they never told me when they needed me until the day, or sometimes hours, beforehand. So I had to keep my entire weekend open on the off chance that they needed me. I would ask them again and again if they could please give me more notice so I could plan my schedule, and they just couldn't get it together. So I would miss out on social events as well as other babysitting opportunities. It was maddening! If they wanted to have me on a retainer so I would keep my whole weekend open on their dime, that would be great! But they wanted hourly babysitting rates and it was just a clusterfuck. I didn't last there long.
Hope this helps!