WOW...you lucky thing!
SF is a WONDERFUL city

Do you know where you'll be staying yet?
Things that are a MUST do in my book (off the top of my head)....
Alcatraz
Ride a Cable car
Walk up - doh! Can't remember what hill it's called - it has a tower (like a mini light house shape) on it...blast...it'll come back to me. It's a killer to walk up, but the views over SF are fab.
Go to Lombard St (the ultimate z-bend road!)
Take the bus across the Golden Gate Bridge and walk back (especially wrap up though - in Feb it'll be c-c-c-cold and the bridge, obviously, is very exposed)
Pier 39 & Fishermans Wharf
Chinatown
Touching the Pacific Ocean
Visiting the big park - can't think of the name of that either

but you can't miss it - it's SF's equivelent of Central park and is huge!
Depending how much time you have there, and whether you have a car, there are also some nice places to go an hour - hour 1/2 from the city (though I'm sure if you didn't have a car, you'd be able to do an excursion to say Monterey (The best aquarium I have EVER been to in my life, which also just happens to be opposite a factory outlet, LOL) or north to Sonoma Wine country and the great Sequoia trees etc.
I just loved SF when I went - and one day I WILL go back! It is a compact city and has real character - you'll love it
