Everyone wants free software!
Free software, I don't know if any. But others on this forum have used Win4Lin,which will do this for you, but it costs.
http://www.netraverse.com/But the question is, why not just use Kmail? You can import your messages from the Windows system.
By the way, your question about modems...it will be very difficult to find a Linux modem for under $25.00. What you essentially need is a hard modem, which are had to come by. I did find one for under $25.00, but here in the US.
Or, you may find one on Ebay, if you have access. Do a search on this forum for
winmodem or just
modem and you will find some possibilities, but maybe not for under $25.00.
What you need is a hard modem. If it says winmodem of softmodem, these will not work, Perhaps some others have gotten some winmodems, or linmodems to work, but I have not tried this.
Dapper Dan had a suggestion on an Actiontek modem that works and I used to use a Diamond SupraExpress 56e, the "e' is important, which means external, which generally means that it has the hardware onboard. It connects through the serial port. You do not want the USB or MAC version, be careful!
If you don't find one, send me a PM, as I still have my modem, whch is not in use and may still work, I have not used it in some time.
Also, look at the following;
http://www.compgeeks.com/details.asp?invtid=CDIMM00131-PB