After several delays, Fedora Core 6 is released and can be downloaded from the redhat downloadpage. I expect the mirrors will be opened within several minutes.
btw: it’s now 20 minutes before the official release which is planned at 14:00 GMT
These screenshots confirm that it is possible to have aiglx on your FC6 box.
I won’t be available by a default install, but with installing some extra packages and changing some config it should work. I guess in a couple of months there will be some howto’s to get those effects working. (Maybe I even post some guidelines to get it working).
On this page all FC6 graphics are gathered (and you can download them in several formats). In another directory of the same users webspace you can find the graphics for RHEL5 which will be released in a couple of months.