Can you recommend a knowledgable guide for these museums? My friends and I would like to book a private guide since we have 6 people.
For the Accademia you won't need a guide. It is a relatively small place with just a few rooms. The only reason really to go there is to see "David" (my opinion). I haven't used a guide for the Uffizi, but instead have used the audio Podcasts (downloaded to an iPod) that Rick Steves puts out.
Just did both of these museums last weekend. I agree that you can download RS free podcasts to tour them (especially for the Accademia). A company that does tours (didn't use because there weren't enough people for the tour to go) is artviva.com. They do an all day tour or separate tours as well. Have fun!