Share Users Between Blogs …

Hi,

Is there any easy (fairly) way to share user info between blogs on the same server (same mysql)?

Wanted to have two or three different blogs for my family (general blog, food recipe blog, etc), but wanted them to only have to register once … of course, would have to login to post to each blog separately but save them one step …

Also interested in integrating bbpress as well.

Are there any guides online to use one database’s user blog for more than one blog?