First, you will need a battery for your transmitter. For the interface option, you can go for any of the following:
- Serial PIC Interface (com port)
- Joystick Interface (game port)
- USB Interface (USB port, simulating a joystick)
The serial PIC interface will limit your setup to FMS, whereas the others can be used on other simulators/games as well.
FMS does not need a top of the range PC. However, it is recommended to have at least a 32MB video card. I am running a Pentium II, 300MHz with a 32MB video card, and getting around 30 frames a second. It is also a good idea to check your version of DirectX. Anything below version 8, I will recommend you to upgrade DirectX.
Have a look on my for a quick link to the DirectX site.