Found this great guide to performing some basic web tasks such as submitting forms, uploading files, and interacting with RESTful services.
In the tutorial Matt goes through using the Cocoa libraries to perform basic web tasks, and also talks a little bit about the excellent ASIHTTPrequest library. He also goes through some principles that you will want to follow when creating RESTful web services. This is a great read on the absolute basics of interacting with the web using Cocoa.
Please post any comments below, thanks.