Christian Heilmann offers us Dishy, a JavaScript REST API for talking to del.icio.us. Taking full advantage of del.icio.us' JSON format and the script element, Dishy doesn't need a server-side proxy. Its a useful helper class for easily getting information from del.icio.us.
Covers all the methods available on the jQuery library, along with inline code examples. Interestingly, the same documentation is also available as XML and JSON.