i've added a new command for AutoTag by Track> Update "Keywords" with Last.fm Tag Cloud for the next update
you can build smart-playlists or auto-dj custom filter using the Keywords tag a filter or search any usual way (Keywords is already supported anyway)
I think its a great feature to have this type of filtering in playlists but its one of those things that will be buried in the functionality unless you know its there, so I'll try and think of a way to make it more obvious.
john6555, "love" support is also now included (infact its in the latest update link but not fully tested) - you can include in smart playlists or auto-dj filters as any tag. It can be displayed using the "Love" tag as a column. Loving a track can only be acheived with right click> Rating> Love or assigning a hotkey. The last.fm api doesnt support "un-loving" a track.
if you want to try out either of the above:http://www.mediafire.com/?qyuydjo24h3
The first time you log onto last.fm, it will automatically sync the loved tracks but you can do so manually using Tools> Tagging Tools> Sync Last.fm Loved Tracks
Note also that tracks can only be matched on name and track title, so if they arent spelt the same between MusicBee and last.fm they wont synch