I have the old black one with a wifi adapter and I use the BT wireless connection at home. I don't think plugging a dongle in the xbox would work as you can't install the drivers etc. Some might do though, never tried it.
I had a few 48hr trials a while ago but gave them all away online to people who didn't get paid or whatever for a week or so and couldn't get online.
As sad as it sounds we have a local tag that seems to get used by most stokies, so we tend to find each other easily if you're in a game with nobody you know online with you, they'll spot your tag and invite you to a game so you end up on their team. Met some good blokes locally to me over the past couple of years. In fact, just about to go for a pint with two of them.