I originally learned to fly in gliders and have about 130 hours logged. I completed two legs of the Silver C prior to obtaining my license but then made the fatal decision to learn powered flight so that I could fly the tow plane. Since then I am really a propellor head, although I too see myself as a glider pilot first.
What would your advice be about approaching my local club or indeed any club? I've been thinking about it. I'm thinking of offering myself as a stand-in pilot, there for whenever weather is good and people want to glide but no tugger. And maybe offering to pay any expenses in showing me how to tug...
IIRC, the current issue of one of the GA magazines (don't remember which one, sorry) has a fairly detailed article on this topic. I just skimmed it at the shop but it looked fairly decent.
As cats_five noted, most clubs - though not all - operate tailwheel tugs. They will not typically teach would-be pilots how to fly tailwheel, and you will be probably expected to have a certain number of tailwheel hours logged before you will be accepted as a trainee tug pilot. At my club it used to be 10 hours total, five hours solo. I believe we increased those minima after we switched to a Pawnee (the Cadillac of towplanes!) ... not that the Pawnee is a difficult aircraft to fly.
I know a few tug pilots who do not soar, but there is no real doubt in my mind that the best tug pilots also fly sailplanes.