Yep, generally the new iPods are available on the day of announcement.
Really? But then you won't know what any of the features are until they announce it, so you'd be buying the iPod blindly without knowing its new features? If you get it immediately of course
First it's your problem if you buy it blindly
They are available on the first day on the online Apple store. Most retailers will have to wait a couple of days.
And I remember that the first iPod touch was only available for preorder at launch. It took at least two weeks before people started receiving them.
They normally have a regular, yearly Apple Conference of iPod's which will be available to watch on Apple's Website, stating any new iPod's or updates that are coming late on in the year. That has been the tradition for years, and i doubt they will abandon that.