I've just posted version 1.5 of phpFlickr for download. In this version, you'll find a few new methods. I've implemented the flickr.groups.search method (which I was somehow missing), in addition to the ability to use HTTP Proxy servers with the "setProxy('proxy', 'port')" method. Another exciting feature is the ability to support 23 (a European-based photo sharing site) now that they have released a Flickr compatible API.
Update: You'll find information about using proxy servers and using 23's service in the "Other notes" section in the readme file or in the documentation.