If you're a regular user of Picasa, you may have overlooked a newly-released feature of Picasa Web Albums.  After you've marked and uploaded pictures to a web album, surf on over to Picasa's web site.  From there, look for the People tab and click it.  Once there, you can look for the face tagging section on the right, and go through the process of identifying faces.  For my albums, I had about 1300 faces that were identified in about 5 minutes or so.

After that, you start the identification process - which basically links identified faces to your Google account contacts.  You can create a contact without any special information, just a name will do.  You can also identify faces that weren't automatically found by Picasa.

After about two hours, I successfully identified about 1100 of 1350 "faces".  Approximately 222 of the 1350 were either not faces (very few) or just people I didn't care to identify (very many).  You can share the name tags (make public), share some album's names, or share none.  Right now, I've left mine as public.  Head on over and check it out.  Maybe you'll find yourself!