At last – your two favourite music services merged together (assuming you aren't from the US in which case it's 1 of your favourite services and one you can't use). That's right, I've just released the latest (beta) version of SpotifyMCE, which brings integration with Last.fm. When you play a track through SpotifyMCE, it will now scrobble that in to your music profile. Download version 0.9.3b for this great integration.
And I know I will get asked about launching last.fm stations from within SpotifyMCE. All I can say is stay tuned.