I read somewhere they can "blacklist" apps which will essentially forcibly remove it from your iPhone... It's there to stop viruses... I wouldn't be surprised if they do that when the iPad comes out, or find a way to stop the program from working with the iPad... Either way, i've got a suspicion it won't work...
The way i look at it, so far what have they had to loose from a small number of people using netshare to tether their macs? Nothing directly... It was the carriers that lost out (well, only in their minds!), BUT the iPad is a different thing; Apple WILL lose out if i tether using a wi-fi only iPad as they could have sold me a 3G iPad, so i think they'll do everything in their power to stop ANY form of tethering on the wi-fi version...
Because of this, i remain sceptical it'll work; soon find out then i get my hands on an iPad