I think it's extremely unlikely to be in the next couple of weeks. If they released it that fast, you could hear the sound of a thousands of developers all screaming at once half-way round the world.. and they're announcing iOS5 next week at the developer conference! If this happens, Jobs might not get out alive 😉
More likely, they'll preview it next week, and give us developers a beta. Then, a few more betas, and a final release alongside the iphone 5/4S/whatever it's called. The phone update is rumoured for september, so I'll go with that.