I just got my first PS3 and it came bundled with inFamous2. Should I play the first inFamous in order to have an idea of the story, or can I go right into this and still have a good time? And if so is the first one a buy or rent at this point?

I don't think you'd have any trouble understanding the events, the second game sets things up nicely.. But I'd still recommend playing through the original game first, it's excellent and you should be able to get it pretty cheap at this point. Plus you get a few bonuses for having a save file from the first.

Yes, inFamous is a great game, and will make inFamous 2 all that better. Besides you won't be able to play inFamous after infamous 2.

Youtube the ending and you'll be good.

I skipped it and understood the story just fine. A lot of people say the games are so similar gameplay-wise so if you burn out on the gameplay during the first one, you probably won't enjoy the second one so much...