Single Sign-On with Coldfusion site

I currently run a site with a large number (6000+) of users. I am investigating the possibility of adding several blog functions to the site, starting with a news type blog and later expanding into individual blogs for each user that wants one. Obviously WordPress MU is the solution to the second issue, but before I can do that, I need to figure out if I can integrate WP with my site to allow for a single sign-on.

My question is how I can automatically create a WP user when a new user signs up on my site, and bypass authentication on WP if the user is already signed on. Has anyone dealt with a situation like this and can point me in the right direction?