Jim Zimmerman

Wow, I had no idea there were so many ajax frameworks. Here is the list of 50 that I found here. I guess it makes sense since it is so new and everyone likes to have full control, so they write their own. I know I did also, but it is no where close to the quality to let anyone else use it.

Although I am slightly biased, my choice is Atlas.
I am now migrating all of my old ajax stuff to atlas. I have played with many frameworks, and Atlas is by far the most complete. It is a little more complicated, but also more powerful. It really is an extension of JavaScript and I predict will be the standard way to implement good practices ajax programming. Anyone wanting to get involved with ajax programming in asp.net 2.0 really needs to be using Atlas. Microsoft is adding some cool features and it will integrate right into the Visual Studio IDE. This is where the future is headed, so no need to learn frameworks that you will be porting from in the future.

Have fun!