I would install FC2 now. From what I've read, FC3 is not going to be an earth-shaking change and is bound to have some bugs at the beginning that you might want to avoid. Yes, you can upgrade from FC2 to FC3 in the future. You might want to read this link for some details and help: http://www.fedoraforum.org/forum/sho...rading+FC1+FC2
FC2 comes equipped with Up2date, which will keep your system current and give you a big red exclamation point when you need to take action. Of course, you can choose to update your information with YUM or try Synaptic instead. All work great!