Apple yanked an application Thursday from its online App Store that would have let iPhone owners share its cellular data connection with a notebook.

Created by Canadian developer Nullriver, the NetShare tethering application was posted for a short time Thursday on Apple's App Store, the online mart for iPhone and iPod touch applications. Within hours, however, it had been pulled from the store.

As of this morning, searches on the App Store for NetShare returned empty results.

"We're not quite sure why Apple took down the NetShare application yet, we've received no communication from Apple thus far," the company said in a statement posted to its Web site Friday. "NetShare did not violate any of the Developer or App Store agreements."

NetShare lets users access the Internet from a notebook by "tethering" it to an iPhone's wireless data connection, essentially turning the smart phone into a movable wireless hot spot.

According to information published about NetShare by such sites as MacRumors, which included screenshots of NetShare's instructions, the application runs the iPhone as a proxy for the notebook. That allows the notebook to piggyback on the iPhone's 3G or EDGE data network to connect to the Web and send e-mail even when outside the range of a traditional Wi-Fi signal.

Null River said it was trying to get an explanation out of Apple, which controls the App Store and determines which applications can be sold there. "We're hoping we'll get some feedback from Apple today. We'll do our best to try to get the application back onto the App Store if at all possible," the company said. "At the very least, we hope Apple will allow it to be used in countries where the provider does permit tethering."

AT&T, the exclusive mobile operator for the iPhone in the US, does not officially allow tethering for Apple's device. However, it provides the service for US$30 extra per month to BlackBerry users.

Apple did not reply to questions about why NetShare was yanked from App Store.

Before it was pulled, Apple was selling the application for US$9.99. By the agreements it strikes with developers, Apple keeps 30 per cent of all sales.