Unfortunately it doesn't look like that app will work. From what I can tell, that phone doesn't have WiFi, and that's what that app uses to share the data connection.

That's really the easiest way to tether your cell phone, honestly. Yeah, you can use USB and bluetooth to turn the phone into a modem, but I've only run into annoying problems with doing that.

So the easiest way is to make the phone take it's 3G data connection and use the built in WiFi to broadcast it back out again like a router. I have that on my rooted T-Mobile G1 and I love it. I just set my phone down somewhere, tap the tether button, and suddenly I have internet on my netbook anywhere. It takes me about 5 seconds and works every time. Essentially this is turning my phone into a MiFi. The other advantage to the modem approach is that multiple people can access the phone at once (though the speeds aren't really good enough for many people at once).

All that said, I'm not positive because it's been two years since I used a Windows Mobile device, but I think that ICS is part of Windows Mobile 5 and later. Try this site's steps, maybe?