I do not agree
http://en.m.wikipedia.org/wiki/Tethering
You are sharing your iPhone conection to a lap top or pc
But if I need to have a wireless card than I can pick up the same signal that my iPhone can .... No point to these apps
Even wireless cards on older pc's have a built in antena so they can pic up the same signal strength as your iPhone and even more ....
The new wireless cards , USB adapters, and those new tiny tumb drive adapter are even stronger duel band ....
In order to set up an adhoc you need wirless card if you have that you can pick up the same signal as your iPhone ... No need for app!
A wireless card will not pick up the same signal as your iPhone, unless it is a 3G adapter. And then, if you did that, you'd have to pay a subscription fee.
The point in tethering is for those who are on the move and need a 3G data connection for their laptop. There's no point in buying a 3G adapter and paying more money per month when you can use your iPhone for free if you're lucky to get one of these apps before Apple pulls them.