I've just put up phpFlickr version 1.2.1. I put this out to correct some typos and a bug in phpFlickr::buildPhotoURL(). I've also changed the way that logging in works. Now, instead of using the constructor, you'll need to use the phpFlickr::login() method. I did this to be prepared for the new authentication scheme that Flickr announced. There is also a comment within the definition of phpFlickr::photos_search() to explain how that method works.
There's no major reason to upgrade to this quite yet, if you're already using the class in an app. The bug in buildPhotoURL is just about the only reason and that's a one line fix I already posted. I mostly put this up so that people who are new to the class will get the right information in the README.txt file.