Migrating from custom user list to MS membership in SQL Server

Sorry, I'm not even sure how to ask this exactly... but I wrote a website with logins. For that, I made my own users and passwords tables and hashed the passwords myself. Now, I would much rather move to Microsoft's built in membership provider with asp.net in sql server. Does anybody know a good way to migrate over?

The only real idea I've had so far is to make both systems run simultaneously, then when a user logs in, vali开发者_开发知识库date them in my old system, then ask them to re-enter their password and save their new stuff in the microsoft's system... then clear the record out of my old system. Eventually, I would hope that would move everybody into the new system. But that seems annoying and messy. Is there some better way?

Sorry if that doesn't make any sense.

You just use the custom membership providers.

Here is a good SO link

How to implement ASP.NET membership provider in my domain model