Use same logins for two wp installs?

[chelle]

I am using s2member pro and have a forum for my site using simple-press forum plugin. However, due to some different issues with another software I want to use I need to move the existing simple press forum to either its own wordpress install in its own folder on the same domain (mysite.com/forumdirectory) or switch it over to a subdomain (ie: forum.mysite.com).

Ideally I would like the members to have just one login that works both for the original s2member site and the secondary wordpress install - is that possible? Would it be possible to that if I were to switch forum software? (ie: phpbb, smf, vanilla).

I read up on this thread but am a little confused about how the sharing the same database would work:
viewtopic.php?f=4&t=4443&p=12917&hilit=multiple+wordpress+installs#p12917

Any ideas, thoughts or suggestions welcome! Thanks in advance!

[chelle]

I think Justin Tadlock may have solved my problem:
http://justintadlock.com/archives/2008/ ... same-users