Want to use the new tethering feature in the 3.0 OS but don't want to pay out the silly money that o2 wants for it?
http://www.engadget.com/2009/06/18/how-to-tether-your-iphone-running-os-3-0-without-jailbreaking/No hacking, no jailbreaking or funny stuff like that, just point Safari at site, accept the download and away you go.
Obviously o2 are making nasty noises about this but as long as you stick to browsing / email and don't go bananas I don't see how they would know?
^^Note, I haven't tried this, I'm not advocating this and I'm not recommending that anyone try. I just don't understand how o2 can attempt to differient between data depending on the device used to download it - a web page is a web page regardless if its rendered on a macbook or an iphone?