New iPhone 3GS Internet Tethering

I am finally going to bite the bullet and move from the Nokia N95 to the new iPhone 3GS. I have fancied one for a while but not plumped for one as i didnt want another lengthy contact. However i am fed up with 3 mobile and their crappy network which is always dropping calls so time to move on. It wont cost me any extra per month so i shouldn't really feel a financial hit.

One of the things that stood out as very handy was the new tethering feature to use the iPhone as a modem. This looked a very attractive new feature. I knew the N95 could do it but this was just another feature to finally win me over.

This was until I saw the extra charges for using it! Bloody extortinate! £15 per month just to use the iPhone as a modem! This really pisses me off to be honest. Why doesnt the tethering usage come under your existing data and wifi usage!?????????

Even though, i will still probably get the iPhone but i wont be going for the tethering! I can get a USB dongle for £5 per month (it think) from Virgin media. My home internet connection for 10MB is only £20 per month! Just how they can justify £15 per month for effectively 3G connectivity is beyond me.

Can anyone tell me why they cant let you use your existing internet when tethered??? Or is it just another way to extract cash - pure and simple!??