How to SMS on iPad?

[inquisitor]

The iPad does neither support SMS nor USSD (those *123#-styled codes by which you can check your balance etc.). For USSD there's at least an app called QueryUSSD which however requires your iPad to be jailbroken.
Say thanks to Apple for depriving your expensive device of such basic features. By the way they do this intentionally to make people unable subscribing to existing data tariffs but instead to enable providers offering special (more expensive) data tariffs for iPad owners.