This group of controls are set up to use AJAX right “out of the box” and a really pretty easy to use. In fact, I have used them in just about every project I’ve done since I found it. It’s really nice! 
Introduction to Anthem.NET - The Code Project - AJAX / Atlas
Jarretf
hi,
Are you try Ajaxium? Ajaxium is designed as an ultimate AJAX engine
for the entire ASP.NET pages including all standard,
custom and most of third-party ASP.NET controls.
In contrast to other AJAX-based approaches and huge AJAX
frameworks, Ajaxium-powered sites remain accessible to all
search engines and old browsers due to an automatic and silent
degradation to the classic ASP.NET.
Just had a look - rather expensive, especially as the new Microsoft offering is free!