I use an iPhone 3GS on pay-as-you-go with o2. For some reason they offer a mobile data package of 700MB for €9.99, but have disabled the mobile hotspot feature on the handset. I jailbroke (jailbreaked?) and got an app from the Cydia store that allows me to bypass this restriction, and gives me the same options as Apple's native feature. With no warranty to lose at this stage, it is well worth it...
I use an iPhone 3GS on pay-as-you-go with o2. For some reason they offer a mobile data package of 700MB for €9.99, but have disabled the mobile hotspot feature on the handset. I jailbroke (jailbreaked?) and got an app from the Cydia store that allows me to bypass this restriction, and gives me the same options as Apple's native feature. With no warranty to lose at this stage, it is well worth it...