you must have data. think about it if you already had wifi you would not need to tether! the iphone creates a wifi hotspot with the tethering app off of the data plan. then your laptop will connect to the iphone and access the internet.
I know, I was talking about my wifi ONLY ipad... Which doesn't have a data plan like the 3G model. I guess I can't get tethering to work on either of my iDevices correct?
But my other question, everyone here with an iPhone using t-mobile, do you guys just add the $20 data plan on your accounts and it should automatically work with your iPhone?