I have a recently jailbroken 3GS and i have some questions about tethering, can anybody point me towards the right thread for that? or maybe ypou can answer the questions for me?
Note that the main feature of MyWi is wifi tethering, which turns your iPhone into a wifi hotspot that anything can access. If all you need is USB tethering, consider TetherMe instead, which is only $2 and merely activates the iPhone's built-in USB and BlueTooth tethering that's normally disabled in the US.
On a 3GS 4.2.1 iOS and T-Mobile, a PwnageTool created custom iOS with Wortels CommCenter patch and T-Mobile carrier bundle does both USB and Bluetooth tethering WITHOUT additional software.
I used PDAnet on my old android phone and it was fine. It tethered via USB to my computer and never had any issues. I'd look into that or TetherMe, like others have suggested, if you only need/want to tether to your own computer.
I personally got MyWi for my phone, it's definitely more polished looking than PDAnet that I used on my previous android device and the fact that it can be a true mobile hotspot is neat.