Unlike most apps that will provide a proxy web service to your computer through your iPhone PDAnet will provide a complete network solution for tethering your computer. Basically, you can use your iPhone as a computer wifi device, without restriction. While proxy apps will work well for web applications, it doesn’t work for stuff like email, ftp, ssh, etc. PDAnet can handle all network traffic. I’m using my iPhone right now to access the internet from my Macbook Pro and it’s quite fast! Check PDAnet out!
http://lifehacker.com/5086490/the-best-way-to-tether-your-iphone-to-your-laptop-for-free

After buying both the iPhone and iPhone 3g, I became frustrated with the typical iPhone problems – spotty 3g network access, no cut-n-paste, etc. As a result, I was excited about the Bold and got one right when it came out. Having used a crackberry in the past was I confident that it would be the device for me.
Recently I discovered a program called