Russ Lavoie wrote:

Hello All,

I am trying to figure out how I could have two separate wikis (i.e. wiki1.domain.com and wiki2.domain.com) share the user table portion of the database so current users in wiki1 would not need to create a new user for wiki2 and visa versa.

Is this possible?

Yes, it is, but seems poorly documented. http://www.mediawiki.org/wiki/Manual:$wgSharedDB Be aware that it is marked as experimental.