For many users Skype crashes when trying to input text. For others Skype will freeze within 30-50 seconds of usage.
According to BigBoss, Saurik has released a new mobile substrate and the issue is fixed. No need for intelliscreen or any other hacks. Just update mobile substrate from cydia. Update to v0.9.2803-1 (or newer) of mobile substrate.
To fix the Skype crash, all mobilesubstrate based hacks are disabled on the Skype app. This means you cannot use voipover3g or backgrounder with Skype app. Do not ask how to do it or point out that it doesnt work. The developer of mobile substrate has already stated that it will not work.