On another note, and I posted this somewhere else, I think it's a really good idea to ask your profs now, before school starts and their time will be very precious. They are probably not doing much during the summer other than catching up on reading, writing, and attending seminars. Make their job easier by asking early, then you won't have to pester them later when your application is still incomplete come November.
I agree, it would be ideal, but since the recommenders need to fill out the LSAC forms, and I wanted to give them envelopes/postage, I feel like it would be better to drop that off in person rather than mail it all.
Would it work to e-mail the profs soon, sort of as a heads up? To ask them if they would be willing to write one, tell them when I need it, and tell them that I need to drop extra materials off to them when school begins? That way, I could notify them sooner, but still have a meeting with them before the letter is actually sent out.