There has been no mention of 3G/4G connectivity for either Surface Model (unlike the iPad which has always had the cellular option since the 1st gen iPad was released in April 2010). It is thought that Microsoft have decided to leave out cellular connectivity with the initial release of Surface and Surface Pro. Perhaps with a view to keep the retail price as low as possible with the launch products and introduce 3G/4G later on once the product has ‘settled’.
Whether or not this will hit the mark remains to be seen. But with the widespread use of mobile tethering through data enabled devices, mostly smartphones, it may not pose a problem. After all the Windows 8 Apollo mobile OS is due to launch soon. A perfect pairing…?