Yesterday, Apple removed an application that would let users tether their iPhone to their laptop in order to use it as a wireless modem. The application, created by Nullriver Inc., was available for a few hours yesterday, until it was removed.

“We’re not quite sure why Apple took down the NetShare application yet, we’ve received no communication from Apple thus far,” Nullriver commented on their website. “NetShare did not violate any of the Developer or App Store agreements.”

AT&T doesn’t officially allow tethering on its mobile devices, most likely in order to avoid the unnecessarily high data transfers incurred when using a desktop browser. However, they do offer the tethering service to BlackBerry users for an extra $30 a month. In all likelihood, Apple was instructed to take down the app by AT&T.