Here's a some very good information on Lyme's, the treatments and vaccine available. It's a little bit technical, but a good read: http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/rr4807a1.htm
This vaccine isn't expensive (I paid $13 for Charlie's) and SO worth the cost. Please check into it if your baby hasn't been vaccinated. Also you should be able to check with the DNR in your area to find out what regions have been designated as a high potential area.
Here's the MN DNR's site about deer ticks. They have pictures and some more information about them. http://www.dnr.state.mn.us/insects/deerticks/index.html