You need a last.fm Account and a Player with last.fm support. See also the last topic of the FAQ
In the folder [wp-blog]/wp-content/plugins/schmie_lstfm2/img/ are 2 images rot.jpg (not listening) and gruen.jpg (listening to music) replace them and make me sad:(
At first you must have an MP3-Player wich send's infos to last.fm. That works great under Linux with Amarok. I think that iTunes can do it to and there's a plugin for foobar2k. The status can also be offline for a short time when you play a new title




