A new Upgrade Centre on MSDN has just been launched to help customers who are already using ASP.NET today to easily move onto ASP.NET 2.0. Check it out at http://msdn.microsoft.com/asp.net/migration/upgrade/default.aspx! 

As part of the launch, the team have also created a white paper that goes into detail of lessons learned, best practices and techniques for developers who are looking to upgrade their apps: http://msdn.microsoft.com/asp.net/default.aspx?pull=/library/en-us/dnaspp/html/upgradingaspnet.asp.

Of course, if any of you have other tips or tricks or lessons you have learned while migrating your ASP.NET code that you want to share - do let me know! We'd be delighted to hear them.