If you'd like to use your Android smartphone as a 3G wireless modem for your laptop or tablet PC (or desktop), then PdaNet can make that happen quickly and easily. This software allows you to easily tether your Android smartphone to your PC so that you can get online. The nice thing about PdaNet is that you can tether either by using the USB cable or via Bluetooth.
I've used PdaNet on Palm OS (Treo).
I've also used PdaNet on Windows Mobile.
I'm now using PdaNet on Android.
You can also get PdaNet for iPhone or BlackBerry. So can you tether with your smartphone?