As this thread has piqued me into looking into this a bit more, I should add a cautionary note: some ISPs actively discourage tethering, and I'm not sure that some don't exclude tethering from your data allowance. I'm with Vodafone in the UK and tethering is plainly and simply allowed within my data allowance. Your ISP may differ - check! One other thing is that if you tether your laptop to your phone you may be using data much faster than if you simply google, etc., using your phone. All those big, full-size web pages you download...