"This version of Skype is only supported on unmodified iPhone OS 2.2." Jailbroken users recieve this notice upon launch of the latest update of Skype. I assume this is due to the (now resolved) problems between Skype and MobileSubstrate. The notice does not impede function of any Skype features, however, and is just a one-shot notice. Still is curious though that App Store applications can realize that you jailbroke.