iOS 4.2 will come out in November 2010
mmm the ipod touch 4g already come with iOS 4
If you bought it before Oct. 12, 2011, it comes with iOS 4.1, but after Oct. 12th, it comes with iOS 5.0
Some time in November
First Thursday of March 2012
Wednesday 12th October 2011
As of May 2014, Apple has not said when the iOS 8 will be released. Speculation is that it will be released around the middle of September.
Sometime late September
It comes with iOS 4.1
it comes out on monday 21st of June according to apple
12-24-12 or 1-1-13
It was realeased for download on September 18th, 2013.