I'm running Windows 7 and there used to be a super awesome option called serial keys in Windows XP. This option no longer exists. I had to find a way to get the input from the com port to dump into the keyboard buffer. After some searching, I located a program called AAC Keys, which is an alternative to the Windows serial keys application. It's lightweight, runs in the tray, and can be configured to any com port you wish.
My original goal was to do a sort of Windows login authentication using my RFID implant's unique tag.... But i'm not going to get into what a headache that was to try to do using an Arduino to interpret the signal. So I have put that project aside and decided to have some fun logging into various sites and applications using my tag as the password. For demonstrative purposes, I changed my Guild Wars password as well as the password to the RFIDtoys forums to match that of my tag. Since the sketch I uploaded for my Arduino automatically sends a 'return' at the end of the tag, it was a simple matter of scanning my tag when my cursor was in an active text box.
This is a video of it in action.
The programs I used for this were:
Arduino FTDI drivers:
All in all, it's a fairly simple little project. I am quite happy with how it turned out. And it gave me a nice little break from fighting with Windows to get my station login system working.