This article (with source code and project files) shows how to make a simple XML-RPC call with the new-in-Jaguar WebServicesCore framework.
This HowTo shows how to use an NSScanner to do simple syntax coloring.
This open source (BSD license) class parses RSS files using CoreFoundation routines.
This open source (BSD license) Cocoa class parses OPML files.
Some cool Cocoa websites...
Cocoabuilder
Searchable archives for the Cocoa and MacOSX developers mailing lists.
Cocoa Literature
Lots of articles and HowTos organized by topic.
Cocoa Dev Central
Lots more articles and HowTos.
Cocoa Dev
All kinds of tutorials and docs on Cocoa.
Stepwise
Articles and news for Cocoa developers.
The Cocoa Files
Articles by Andrew Stone of Stone Design.