Swindled into a contract

I'm furious that AT&T made a service change to my account which involves a 12 month contract.  I asked repeatedly on my call if this was month to month or contract, so this was a big surprise to me. I cannot resolve this with them since they are closed for the weekend but I'm wondering what my recourse is. I'd appreciate any advice or help.  Here is the story:

I called AT&T early December to go through my annual dance to get reasonable DSL service after AT&T jack up my payments.  All I need/want is dry-loop but last year it was cheaper for me to go with bundled home service and DSL.  This time I was ready to cancel since finally cable became available in my area.

So, I call to see about better options and the first attempt ends up fruitless - I'm apparently on the best deal.  I hang up and call the cable company to check and their deal is ok.  So, I recall AT&T to cancel service.  Very different response: they offer me a reasonable bundle deal and I decide to stay with them (BTW: if only they'd give me this rate permanently they'd have a permanently happy customer, not an annually angry one).  During the call I ask about this being month to month no contract, and I'm assured yes.

Yesterday I return from a trip and read the bill: you guessed it: 12 month contract.

What I would like to do now is cancel service entirely.  I've had it.  What are my options?

Thanks!

Dave