You don't need shareware or freeware to do this. And you don't need to change your ISP either. Just click your way to the Dial-Up Networking window (Start--Programs--Accessories). Open the Connections menu and choose Settings. If you check Redial you can choose from a range of dialling options.
Bear in mind, however, that Austel (the Australian telecommunications body) regulates the use of modems on public telephone networks, and some repetitive dialling techniques will void your modem's Austel permit. In which case, you may be liable to a hefty fine. Austel regulations should be detailed in your modem's manual.
- Neville Clarkson

The Dial-Up Networking dialogue provides several redialling options