T.S.
http://www.ides.state.il.us/household/employer.asp
http://www.babycenter.com/refcap/baby/babychildcare/5946....
P.,
I breifly looked into the option of a nanny when I got pregnant with our second child (due in August). Our child care costs in 2008 will be about $25,000 to have both boys in a local center.
Based on what I looked into, we would have to pay a nanny as an employee. Which means that we would have to be an "employer" and pay employer taxes on her salary. With that being the case, and we offered a salary of $25,000, our employer responsibilies would add on another 7.65% ($1912.50). That's not that bad and probably worth it. But, in our situation, the girl (whom we loved) that we were considering was going to quit her current job that provided health insurance for her. The cost for health insurance (about $250/month = $3000) in addition to employer taxes meant that either we paid about $5000 a year more out of pocket OR we had to offer her only $20,000 a year. I wasn't comfortable with either option.
Luckily, we are very happy with our center and although the idea of having the young woman at our house constantly pops up in my mind as temptation. For now, we are content.
Good luck, and I'm anxious to read other responses on this.
T.