Try
Toastmasters. There are clubs all over the world, they're a great place to meet people and gain confidence in not only giving speechs, but you'll also get help with handling any kind of social interaction which requires talking.
Seriously. As David said, this kind of change requires getting out there and experiencing it. Tapes can help, for sure, but you'll get much further if you combine them with active participation. And even better, you'll get heaps of constructive feedback, that's a big part of the Toastmasters thing (and if you're unsure you can just go along to a club as a guest to see what it's like. You don't get thrown in the deep end straight away).