It appears that there may be a problem with tethering on the iPhone on O2 UK, as apparently testing internet tethering on the iPhone and O2 network as an iPhone/MacBook Pro combination is delivering poor results.

Tethering on the iPhone 3Gs has been tested by the guys over at Intomobile and they found it wasn’t too good, although most of the preliminary tests were done in average data coverage areas, so they tried areas with good 3G coverage.

Even then data rates weren’t that good. Now they believe the tethering implementation may be buggy as tethering managed to completely lock the iPhone 3GS and crash iTunes on the Mac. They say the iPhone 3GS should be a great data modem, but wonder if there is too much going on inside to dedicate enough resources to tethering.