There are lots of web sites of potential interest to developers. This is a partial list of some of them.
Metrowerks, the leading provider of Macintosh development tools, makes Magic Cap tools, too! The complete CodeWarrior/Magic tool suite is part of CodeWarrior Gold. Metrowerks also offers really great discounts on Magic Cap devices with their developer bundles.
Sony's Magic Link is hot! Sony's info center has updates on all things Magic Link.
The Motorola Envoy is an out-of-the-box wireless communicator running Magic Cap. Check out Motorola's site!
The Spies Magic Cap Freeware Archive has all kinds of stuff for Magic Cap communicators! The latest and greatest Magic Cap freeware packages are here in both Mac and Windows MagicXChange formats.