I recently spent some time with the Bamboo product managers in relation to user management and administration. Often you have to have a problem to understand the solution, so to help you bring this full circle I walk you through some of the challenges of SharePoint extranets... something that's becoming more and more common.
In a three part series over at the Bamboo team blog, I essentially walked through the challenges, and various solutions from freeware solutions and source on codeplex, and various ISV solutions from the extranet collaboration toolkits to full user management suites.
As readers of my blog you get a sneak preview as these posts have all been drafted, but scheduled to be released over the next couple of days.
In these you'll find some real nuggets like site creation, user creation, password management and notification... very frequently requested and common needed functionality for extranet deployments. Based on what you need you'll find the above solutions cater from point solution to fully featured suites. Don't be afraid to give them feedback or ask for features. They just might build 'em.