Don't know if you use a CP or not. I use cpanel and I followed [iG]'s Guide here
Haven't made the jump to FC3 yet. Actually I'm debating even staying with Fedora. Not that I've had any real issues, but sheesh the lifetime is short!
Here's another guide I've been eyeing for when the time comes
The only hangups I personally had were with the existing redhat-config rpms causing dependency issues during 'yum upgrade'. Basically I just removed the problem rpms and let yum reinstall them later on if they were called for.
I also agree about moving step-by-step. Yes definitely.
Good luck let us know how it goes