Microsoft is teasing their new mouse, with a new pointing system designed to work on any surface:
Coincidentally, it's the same day Apple introduces their new line-up. I say coincidentally, because it would be asinine to try to compete for news space on an Apple announcement day, esp if Apple drops something really cool - even a cool new mouse will have little effect against that.
Rumor has it that this is the new mouse (not really rumor, since the logo is obvious):
It has some sort of new pointing system (see
Crunchgear for analysis) that will benefit the any-surface user - usually the traveller or if you like to have a mouse on the couch.
Built-in wireless (with USB stick, blah). Neat, though. Depends on price and size. Not the prettiest mouse, but it's just a portable.