I've recently been corresponding with a few developers new to ASP.NET who are struggling with storing personal information in an ASP.NET membership application. I've encouraged these folks to adopt the use of ASP.NET Profiles instead of trying to reinvent the wheel.
In an attempt to prove to them how easy it actually is, I created a simple app that demonstrates how you can store information along with a membership user. The complete website is attached.
One thing to note since it's not immediately intuitive; Profile properties are defined in the web.config file. Once you add new properties, you'll need to build the website for them to be "seen" in IntelliSense.
Jim