VS 2008 out of the box allows you to open and edit existing
ASP.NET 2.0 applications built with the separate ASP.NET AJAX 1.0 download we
shipped last year. The VS 2008 multi-targeting support works just fine
with these projects, and you can use the improved JavaScript and web designer support with them - while still targeting .NET 2.0 and ASP.NET AJAX 1.0.