OLPC has set up a nice getting started guide and a support page for the XO laptop, as well as a support FAQ. Things are still clearly in their early stages: the Give1Get1 laptops are shipping with software with known issues (no WPA wifi, no sleep feature, no printing) that will be addressed in a software update in the near future. But the newest photos and screenshots make it look pretty slick.
G1G1 participants should start receiving their laptops this week on a first-come first-serve basis. The G1G1 program runs through December 31st, so you'll still be able to jump in after reading dozens of reviews from other G1G1 participants.