Yep, they're just after secure info.....
If I talk to a person (and I likely won't even answer the call to start with), I ask them to send me a letter/information because I don't make transactions over the phone. Of course, they never send me anything.
I once got a call telling me I'd won the Publishers Clearing House Sweepstakes. I said I thought they were a scam, because first of all, I didn't think they would call me first. They could never convince me. The caller sounded foreign, and that always makes me suspicious. He didn't sound at all like Ed McMahon (sp?).