Two new phone models, you mean like each year for the last 2 ? You don't say.

We've known for a while that there would still be an iPhone 4, just like there's still a 3GS for sale right now and there was a 3G for sale back in June 2010. This isn't a surprise.
And with the timeframe in which they are shipping this year, it's unusual but not surprising they would "upgrade" this lower end model.
As for the 5 production delays, I wonder what kind of goodies are in there to warrant such a thing if it's true. It's not like we have heard rumors of some spectacular features, everything we've heard is quite common in other phones by now (4"+ screen, 8 MP camera from Sony, black and white models...).