Cliqset Libraries
Java Library - A Java library for interacting with the Cliqset API. This is the very same library we use with Cliqset.com.
PHP Library - A full featured PHP library for the Cliqset API contributed by the guys over at Prodesio.

Sample Apps
Cliqset Mobile for iPhone - An Obj-C iPhone social networking application built upon the Cliqset platform APIs.

OAuth Resources
OAuth Specification - Detailed information on the OAuth Core 1.0 specification
OAuth Libraries - A collection of OAuth libraries contributed by the OAuth community

REST Resources
REST History - A detailed overview of REST.
Introduction to REST (Video) - Joe Gregorio of Google goes over the basic principles behind REST.
RESTeasy - a JBoss project that provides various frameworks to help you build RESTful Web Services and RESTful applications in Java.