Look into the android app FoxFi
urns your Android phone into free WiFi Hotspot - no rooting or tether plan required. Just install and turn it on. Bluetooth mode works for all phones. WiFi mode currently works on most Samsung/Motorola/LG phones. WiFi mode does NOT work on Motorola Droid 1, Motorola Triumph, Samsung Admire, LG Revolution or any HTC phones, use Bluetooth mode instead.
You can connect from any computers or tablets or even game console. Access Point is infrastructure mode with WPA2 security. FoxFi usage is covered under the same phone data plan you have.