ASP.NET Security - Create Users and Roles Programmatically

Hi ,
I am receiving data from an external source via query two strings i.e.e.g. user & pwd. For operational reasons I cannot use the Web Site Admin Toolto create new users. Is there a way I can programmatically create the user name and password (e.g. via a page load event) and also programmatically assign a single (the same)role to all the users I create. I have aspnet security tablesonmy local SQLserver.

Regards SteveJ