There has been a lot of speculation in the last month after some mock-ups and UI video of the new iPods leaked.
Today many sources reported that Apple will be holding an event on September 5th to present some innovations to their digital music players lineup.
The invitation features a cover flow style front with the foremost album cover containing a silhouette iTunes dance holding an iPod (and the other album cover being Beatles' albums).
Speculations say that Apple is going to announce OS X based iPods, probably an iPod Nano 3G with a new form factor (here a mock-up), a full-screen touch iPod (here a mock-up). And probably (as the "The beat goes on" tagline and the album covers suggest) the launch of the Beatles on iTunes.
And last there is also a possibility that some of the new iPods will be able to wirelessly control iTunes, both acting as remote for iTunes and also streaming music stored on a computer to the iPod.
Personally I like to think that the new form factor mock-up is about a new 6G iPod video or maybe even a new model, but not about a 3G Nano, since it is already small, and making it even smaller will make it more difficult to handle (not saying that then all my Nike+ armband and t-shirts will be useless as they were designed for the slim 1G and 2G Nanos).
Already enough speculation and echo chambering for today: let's wait next Wednesday and we'll see what Steve Job is going to announce.