Depends on what you use.. I suggest trying to do the 2.6 upgrade via Fedora Core's up2date service (it's in the menu there somewhere). It's the quickest (and most painless) way to upgrade.
http://www.redhat.com/support/resour...ernel-upgrade/
There's a quick how-to site for you. I haven't looked at it much, so not sure if it's exactly what you need. If it isn't, google
For FC1, general packages (in rpm format) can be found at
www.freshrpms.net. Otherwise, check out Freshmeat or Icewalkers, find some cool-looking pacakges, download the source, uncompress/configure/make/make install it (the site will usually have some cool "Quick install" instructions)
Need more info? just let me know.