Varnish is a state of the art http accelerator, or frontside cache, if you like.
varnish-3.0.0 was released some weeks ago. I have built packages for Fedora and epel4/5/6. Packages may be found at the usual http://users.linpro.no/ingvar/varnish/. The rhel packages require some dependencies pulled from epel.
Varnish Software produces their own packages, based on the specfile I maintain for Fedora. The changes from their rpm spec are mostly cosmetic to fit better to Fedora’s packaging standards.