The latest news from Apple on the iPhone was on March 6th, and at that time Steve Jobs said it would be released in June while the slide behind him said it would be "late June." There will be another keynote event from Apple on Monday, and analysts expect we'll hear more then.
The next version of iPhone software will focus on third-party applications and enterprise data-syncing. The link below has a video that explains those features. Reports also expect the next version of iPhone software to enable features for the next handset Apple makes: things like 3G, GPS, Video, etc.
Despite what people claim to know, nobody can be sure until Monday.
