The Dummy Provider: Testing membership and roles

Asp.net has a wonderful system built in for handling user accounts and roles. The administration interface is encapsulated in a separate web site that can be accessed from within Visual Studio but it is difficult to integrate into the site. This often leads to building a new user administration area in each site. The problem I have with this is going into the data store and deleting the incomplete test data and not having "known good" data for testing.