Currently Fedora 10 and Fedora 11 should both work. Fedora 10 will be phased out soon.
A full build using sugar-jhbuild will require about 3 Gig of disk space.
Except for the packages mentioned by
./sugar-jhbuild depscheck (please see the non-distro specific instructions) nothing else should be required.
If you notice that any package is required, but not mentioned by depscheck, please file a bug report (login required first, but currently no automatic redirection to login page) against the sugar-jhbuild Component on the Sugar Labs bug tracker.