Atlas now has a Go Live License with the March Release available here: http://atlas.asp.net/Default.aspx?tabid=47
If you want to see how Atlas makes implement AJAX amazingly easy, check out Scott Gu's video: mms://wm.microsoft.com/ms/uifx/asp_net_atlas.wmv from the MIX 06 Keynote.
This is an empowering technology that brings "Web 2" (or "Live", depending on your viewpoint) to all asp.net developers, and really is a must if you want to stay competitive over the next 12-24 months.
Ian