You can do it if you've jailbroken. Haven't looked for non-jailbroken stuff. On my 3GS, I can vary up to 20 dBm depending on how I'm holding it, how I rotate m

You can do it if you've jailbroken. Haven't looked for non-jailbroken stuff. On my 3GS, I can vary up to 20 dBm depending on how I'm holding it, how I rotate myself and/or the phone, where I'm holding it in relation to my body, etc.