I grabbed them using bittorrent.
md5sums matched.
CD 1,2,4 failed the test - 3 passed.
Burned a second set - 1,2,4 failed, 3 passed.
At that point I figured if the md5sum from the torrent was fine, and the same 3 of 4 failed twice in a row, that they were probably fine.
Install went fine despite them having failed the installer check.
But FC3test3 is out, so before you redownload, wait for those mirrors to open.
If you already have FC3T2 you can yum update now - but it's a lot of packages, so wait for mirrors of the FC3T3 iso's to become public, and then grab them using bittorrent.
http://torrent.linux.duke.edu/
When it is public, there will be a torrent there.
FC3 final is due soon enough anyway though, unless you need to test - wait for that.