The Nexista authentication and user administration code is coming along. These packages were written by another and I'm just maintaining the code to keep up with changes made to Nexista. I'm working to make the code more abstract as well, so that it can be used for other things.
I'm going to check out the PHP PEAR Auth library soon too, to see how that might work as well. Eventually Nexista and its apps will be structured as PEAR packages, complete with their own channel!