Following on from my earlier post about the Mendeley API, I've bundled up my code for OAuth access to the Mendeley API for anyone who's interested in playing with the API using PHP. You can browse the code on Google Code, or grab a tarball here. You'll need a consumer key and a consumer secret from Mendeley for the demos to work, and if you're behind a HTTP proxy you'll have to tweak the code (this is explained in the ReadMe.txt file that comes with the code).
The code is pretty rough, and doesn't use all the Mendeley API calls, but I've other things to do, and it felt like a case of either bundle this up now, or it will get lost among a host of other projects. The Mendeley API still feels woefully under-developed. I'd be more interested in developing this client further if the API was powerful enough to do the kinds of things I'd like to do.