The price of $19.99 for the MyWi iPhone App is a lot better than paying AT&T $25 per month for tethering you should be entitled to under your data plan. Paying $300 per year for tethering is absolutely ridiculous and those who are on T-Mobile already can do it for free. However, now AT&T is warning those who are tethering to pay but it is not clear to me that they can do anything about it.
Create an iPhone WiFi HotSpot or iPad WiFi HotSpot without paying $25 per month. Wherever you are - you can connect your laptop or another mobile device to your iPhone / 3G iPad easily without paying for an additional data plan. MyWi 4.0 now works on iPhone 4 IOS 4 and will also work with all jailbroken iPhones on T-Mobile (including 2G/3G/3GS/4) and iPad on 3.1.2 or later.