I've just put out a new release of phpFlickr. I have updated all of the methods to the latest API version. As is usually the case, some of the methods I updated will break your existing code so that it can be compliant with Flickr's API docs. If your current version is working fine, there won't be much reason to upgrade until you need a new method.
In addition to the method changes, I also added a "medium_640" option to the buildPhotoURL function, so you can start using those nice larger images.
You can download the files from the phpFlickr Google Code page.