Hello from down the road in Seattle!

I like the look and feel of the Gossamer Threads forums and am interested in integrating the user database used by the Gossamer Threads forums with other parts of my site. The other parts of the site could use the forum database. Or, the forums could use some non-forum login database. I will also need to authenticate against the user database from a program that's running at a server off-site. I want this all to be done reasonably securely, e.g., say using server and client nonces. Any ideas? One thing I noticed is that the Gossamer Threads forums send the user name and password in clear text from the login page, so hopefully the integration with other parts of the site would eliminate that somehow.