Tethering on an unlocked iphone

[ciaran90]

hi
a couple of months ago i got my iphone 3g unlocked by apple. i was on O2 at the time but last week i moved to Three. When i went to try and use tethering Settings crashed and i returned to the home page. when i returned to try and tether the option was gone.
any help would be greatly appreciated
thanks in advance
Ciaran
iphone 3g (running iOS4)

 

[the.sheepdog]

May just be me but the OS upgrade seems faster on my 3GS. I havent found any glitches yet in what I do. so far nice!

That said, I cannot find tethering anywhere on the new OS.