Tip for Troubleshooting Netshare wireless tethering
Sometimes I can't get my laptop to tether to the iPhone, so I use this trick to "wake up" the iPhones AT&T data connection. Do the following if you've followed the first post's directions to a T and you still can't connect:
1. Go to the wifi settings on the iPhone and shut it completely off
2. open MobileSafari (or just wait) to get the iPhone to start using the data connection (3G or Edge), make sure you see the little "E" or "3G" symbol on the phone, NOT the wifi broadcast icon
3. *now* go back to the iPhone's wifi settings, turn it back on, make sure it's connecting to the "iPhone tethering" access point (or whatever you named it)
4. quickly open up NetShare, hopefully the laptop will connect now
NUTSHELL: Basically just make sure the AT&T data connection on the iPhone is on, *active*, and working; THEN open up NetShare to broadcast that connection to your laptop.
Edit: I'd like to emphasize my use of the word "active" again. You have to make sure that the iPhone is not only switched on to using an AT&T data connection, but that it is actually in use. This means that the iPhone is not only listening for the data signal but also that a connection has been made with an AT&T cell tower. In other words, make sure you actually see some data going into your phone when you open up MobileSafari; browse to a real page and see something. Then switch on the wifi and quickly open NetShare before the iPhone decides it prefers the wifi over the 3G/Edge.
One more note: for anyone who's saying that NetShare is buggy because it doesn't seem to work reliably, it's only "unreliable" because of the iPhone preferred connection can be switched on the fly automatically be the phone. Apple put this (good) behavior on the phone for a reason (switching from wifi->3G or vice versa when appropriate), which is what makes NetShare work only sometimes. Which is why you have to force off the wifi when it is currently in use by the iPhone. Which is also why your NetShare tether will stop working when the phone goes to sleep (it switches off the 3G to save battery life) after a few minutes. This modal switching behavior is good for usability and battery life but bad for an app that (hackily) depends on a stable connection mode.