I decided to improve one of my asp.net sites to add ajax support. I haven't done ajax in asp.net so I googled it came across this video. Just watching it looks like it's a lot of fun. Writing ajax in php is kinda dull, for me anyway. http://www.asp.net/learn/3.5-videos/video-362.aspx Can't wait to get started.
Lot of cool stuffs with AJAX, I am sure you gonna love it There are few other vendors that offer different versions of the AJAX which works with ASP .NET, you may wanna check out them as well.
Using ajax in asp.net is very funny. It's very easy and you dont have to use javascript. Asp.net's Update Panel is doing everthing for you. Just you should call UpdatePanel1.Update() method.