How can I access my computers hard drive from my PDA?

I have a PDA and would like to be able to access my computers hard drive over the internet. My pda is running windows mobile and my computer is running Ubuntu 8.10, but I have wine installed so I can run windows programs. I would like to do this for free but if that isn't possible then I would prefer a one time expense over a monthly charge. Thanks in advance for any answers!