There will be a new iPhone out this year, but most likely it'll be a minor spec bump similar to 3G to 3GS. I'd imagine a move to a 1.2GHz processor, more efficient battery, possibly a move to 1GB ram and a camera bump. Not a lot more they can meddle with.
Next year is when they'll introduce a dual-core processor and 1080p video, when it's standard in every other smartphone so all the fans can say "it might be standard but Apple are the first to do it properly". Dual core chips are too expensive at the moment for Apple to maintain their insane margins, thus I seriously doubt the move will be this year.