I just noticed that UBB.threads is still using MD5 hashes for the passwords. Is there a special reason for that?

I ask because PHP 4.3 has already support for SHA1 hashes, which are even more secure. It should be fairly easy to implement SHA1; after older MD5 based passwords could be identified by the different string length (MD5 = 32 digits, SHA1 = 40 digits)