The Armageddon Decade rating appears to have been applied for by Microsoft, which probably means this Worms edition will be an exclusive XBLA release and is a different project than the PSN's upcoming Worms. If the awesomeness that is Worms Armageddon is anything to go by, the XBLA's special Decades edition should be one of the most enjoyable Worms titles to date. That is, if Team 17 doesn't skimp on the weapon selection.
Update: Team 17 just informed us about the differences between the upcoming Worms games. The PSN edition will be an enhanced version of the XBLA release, including more weapons, additional levels, new audio and 1080p support.
The XBLA release of Worms Armageddon Decade (which we're told is subject to a name change) will be a "vastly expanded edition" of the original XBLA Worms, that will include weapons and features from Worms Armageddon as well as other brand new content. More details to come.
[Via GamerBytes; Thanks Ryan!]