Yes, it is called Friendcomparé. To describe it simply, it lets you compare your musical tastes with your last.fm friends and neighbors. You just enter your last.fm username and it brings up a list of your friends and neighbors with whom you can compare. Once you choose to compare, it shows you the top tracks, artists, albums, tags, friends as well as recently played tracks that are common between both the users.
Though it isn’t anything huge, I am happy with it. It took some effort, probably more in the design part than in the development part, to get it somewhat pleasing to the eyes and yes, functional. But it was a fun and learning experience. Along the way, Sameer gave me some brilliant ideas and criticism, for which I am grateful to him. Also, a couple of people at my favorite IRC channal, #think-digit, who gave me criticism and a third-person point of view, and also appreciation :)
As I went on coding and adding new little features, I learnt a lot on creating CSS layouts and programming with PHP. I learnt a lot more CSS tricks which are definitely going to help me out in my next webdesign project ;). And while coding with PHP, I eventually got hints about its object oriented nature and that how it could make expanding the application a very simple task. In future, I would probably like to make use of AJAX to make it a little more web 2.0 :)
I have this idea of probably building a facebook or orkut application for it, will it be useful? You can let me know in the comments.
Here are a few screenshots:
Build.last.fm - http://build.last.fm/item/433