A friend uses
http://www.access-4-free.com when visiting her father in Florida. They have a TON of access numbers all over the place and the price is pretty good, max of $10 per month. She's a gamer, which means she has used it for lengthy connections without trouble.
I haven't had a need to use it yet, but I've kept the information just in case I'm away from home or in case someone else is looking for something like this.
