Microsoft goes ColdFusion crazy at CFUNITED
Brad Abrams of Microsoft gave a great presentation on the Atlas framework. Atlas is a javascript library for performing Ajax like functionality in web abblications.
At the end of the presentation they showed off a library that Microsoft wrote that translates ColdFusion objects into JSON (Javascript Notation).
Brad mentioned that Atlas is platform agnostic, and will work on IE as well as Firefox and Safari.
He also said that asmx pages have the ability to output in JSON by adding a /JS to the end of you asmx url.

Correction noted.
As far as Atlas working with other Ajax frameworks... we totally want to enable this, and we have people working on it now. If you run into issues, please let us know.. http://atlas.asp.net