The only software you need is the drivers that come with the monitor. Most computer shops will carry (or at least order for you) touch screens.
The only thing touchscreens do is when you touch it is moves the mouse to location you pressed and clicks. So nothing more than the monitor and its drivers are needed. The monitor itself will come with a special attachment that will plug either into the serial or usb port that will enable the touchscreen to move the mouse.
AMD Athlon 64 3000+ (Overclocked to 3300+)
1GB PC3200 DDR
2x200GB Seagate SATA RAID 0
BFG 6800GT OC w\\128MB Ram
2x 19\" Samsung 930B LCDs