I remember when I tried to implement a Login control in a ModalPopup with one of the early release of what was called at that time Atlas and is now called ASP.NET AJAX. I had lots of difficulties and now it works like a charm.
This time I would like to have a Login control in an ASP.NET AJAX PopupControlExtender from the ASP.NET AJAX Control Toolkit.
It was a straight move from RC to RTM and I have managed to have it online after deploying it to staging, doing some tests and then deployed it Production, thanks to Web Deployment Projects.
Here you can see an ASP.NET 2 Webpart on Tech Head Brothers using ASP.NET AJAX 1 to browse all news of the site on the home page:
During the integration of ASP.NET Ajax RC on Tech Head Brothers I had issues with some javascript failing both in ASP.NET Ajax and Adsense. After a short online discussion with Cyril, he could manage to get a fix, and to identify the issue in the ASP.NET Ajax RC. You might read more about it on the forum, or on his french blog.
Adsense uses the native method Date.parse of JavaScript. ASP.NET Ajax RC overload this method changing a bit its behavior. Luckily the old method is saved in Date._jsParse. Using this code just before your first insert of the adsense script will solve the issue:
So they finally released a first Release Candidate of ASP.NET AJAX. You might get an overview of what did change between beta 2 and RC on this page.