According to the latest rumour, the iPhone 5 is due in June. The Korean site ETNews: http://goo.gl/ZK1vF says that it will arrive sometime in June (the Google translation of the Korean is not clear which date).
However, some aspects of the article don’t seem to hold water, such as its mention of the iPhone 5 being released in Korea soon after its début, as Korea only got the iPhone 4 on March 16th this year! There were rumours that Sony are producing 8MP cameras for the iPhone 5 but if that is true then its likely that the iPhone will be delayed by the impact of the earthquake and tsunami, perhaps to September.
Could be though that someone else is actually making the cameras and if this is the case, say Samsung (a Korean company) there may be some deal for an earlier release in Korea – who knows?
Would be nice if the iPhone 5 made it out in June though. I have held of buying the iPhone 4 on the expectation that the new model would be here in June. I will be disappointed if I have to wait until September.