NetShare’s on again/off again relationship with Apple’s App Store seems to be off again. The application was pulled from the App Store again on Saturday without explanation following an equally unexplained pull on Thursday and a reinstatement on Friday.

NetShare is an iPhone application that lets users "tether" their handheld, or share their phone’s wireless data connection, with their laptop. The application was first released through the App Store on Thursday, but by Thursday evening had been pulled and was no longer available for sale.

Nullriver, the company that developed NetShare, claimed that it was not given any reason why its application had been removed from the online store, but many people speculated that it was pulled because it violated AT&T’s iPhone service contract terms and conditions in the United States.

The App Store is Apple’s iTunes-based distribution system for third-party iPhone and iPod touch applications, and is the only avenue for approved applications to be installed on Apple’s handheld devices. Now that NetShare is once again missing from the App Store, there is no way for potential customers that haven’t already bought the application to do so.

NetShare’s up and down relationship with the App Store is not only causing headaches for Nullriver since Apple doesn’t appear to be communicating with the company, but it is also causing confusion for consumers that who can’t be sure the apps they are looking for will be available from day to day. Apple is also sending a message to developers that their previously approved applications may not stay that way, and that message may make some of them think twice before submitting more applications to the App Store.