MaryP - thanks so much for the suggestions - and great point on sleeping schedules!
I should report back, actually - my daughter has now been in daycare for 3 weeks. She goes 9-3 every day, then a few times a week we have a sitter who comes to the house for a few hours so i can get more work done. So far, I'd say she is doing very well. The first week was really rough - she didn't sleep in daycare at all, so by 4pm she was a little monster. She also was very nervous about going. But then I think being with kids her age and doing all those fun activities got her into it - this week was pretty good, actually. She has started taking short naps there and seems to really look forward to going in the morning. It's definitely more hassle for us than with a nanny - which I know, was a luxury! - but I think we made the right decision for her age.