Apple releases their products like clockwork. There is no question of when the next iPhone will drop, the only question is, what features it will have. The one thing that is pretty much a guarantee is a bigger screen, because nowt that Apple is getting smashed in sales from android's big screen phones it really is time for them to play catch up.
the original iphone came out in 2007
the iphone 3g came out in 2008
the iphone 3gs came out in 2009
the iphone 4 came out in 2010
the iphone 4s came out in 2011
so yes there will be a new iphone this year, no questions asked...
I think September is usually when they do their releases.