I've always classified Arms warriors as burst damage and Fury warriors are consistent damage. A lot of people will disagree but that's how I view it :P
Anyways, if you choose to go Arms pick up a nice 2 handed weapon to take advantage of the big damage and crits from MS. Fury will tend to duel wield to take advantage of bloodlust and rampage. That's the typical cookie-cutter view of a warrior spec.
Well, you're just starting the game and lvling from 10 - 70 (Lvls 1 - 10 is considered a "tutorial" :P) will give you plenty of time to learn your class. Once you hit lvl 40, you should have a clear overview of your class can and cannot do and what you are expected to do in groups.
My best advice is, take your time and enjoy the game. Since this is your first character, don't try to rush to 70. Do some light reading, talk to warriors of different specs to see what they say and get some tips on how to effectively play a certain spec.
That's what I tend to do and I've learnt a lot by talking to a random warrior with a cool weapon (ie: Warblades of Azzinoth - Wowee on Elune xD) or a cool shield and asking them what it's like to do this and that, should I be getting a certain item, etc.
Welcome to WoW !!!