Welcome to the forum Greggles.
There are a few options.
1. This is the easiest way but won't technically remove it from your phone but will stop it from running in the background. Go to settings, application manager, all tab, find the 3 app and press disable.
2. Root and remove the app. If you follow this guide you should be fine
Rooting Galaxy S2 - Dummies Guide
3. Install an unbranded firmware on your phone which will remove all carrier branded bloat.
You can the get the latest unbranded firmware from here, the country of origin won't matter
Instructions on how to flash can be found here