Hi Forum,
I found your suggestions whilst looking for a solution to allow me to print to my Epson PX650 printer directly from my iPad 2. I use Windows 7 x64bit on my PC. I chose FingerPrint in my case as it doesn't care what type of printer is in use, so it allowed me to use my current printer. I figured £7 for a solution such as this is fantastic value, especially as you can trial before buying for a week!
So... I installed the trial copy of FingerPrint program without hitch but my printer was not immediately available for use. Fingerprint showed the printer as available on the PC, but it wasn't seen by my iPad. After a bit of Googling, I managed to sort the issue. In my case I had to enable a couple of ports on my Linksys WAG320n router and my PC Firewall.
Here's the screenshot of the settings on the Linksys page in the hope that they help others.
Remember to allow these ports through the Windows Firewall too.
I hope this helps someone else.