The rumours will soon come to an end: Apple has sent invitations to members of the press, including our sister title Macworld, announcing an iPhone-themed special event on October 4 at 10am PST (6pm in the UK) in Cupertino.

As with most Apple event invitations, details are scarce. But the invitation featured four icons for iPhone apps: Calendar, with its icon displaying Tuesday the 4th; Clock, with the time displaying 10:00; Maps, with its usual icon, which displays Apple’s Cupertino campus, and the Phone app, with a “1” badge.

So what’s likely on tap for this event? Apple already previewed iOS 5, the next major release of its mobile operating system, at its Worldwide Developers Conference in June, and said that the update would arrive this fall. iCloud, the company’s forthcoming cloud storage and syncing solution, was showed off at the same time, and former Apple CEO Steve Jobs said it would arrive concurrently with iOS 5.

But the big question mark surrounds the announcement of a new iPhone model. Having foregone its customary summer launch of a revamped device, many expect Apple to roll out a new model—or perhaps even more than one?—at this event. But might we also see an updated iPod touch? New iPods of any other ilk? It’s all up for grabs.

Look for full details here on the day.