it won't take you several months. i just did it, and it's not rocket science. just don't be afraid of it. here's the thread for the build i'm working on, which is more complex than the SS you're building: http://www.bikeforums.net/showthread.php?680528
if the frame doesn't have a bottom bracket already installed, find out the width & threading of your bottom bracket. that will be something like 68mm, and it's either "english" (non-drive side is reverse threaded) or "italian" (regular threaded both sides).
The only thing that will have to be different is the back wheel(or if youre building your own wheels, the rear hub) You will also probably have to get an odd sized bottom bracket spindle legnth. And a lot of people like the looks of single speed cranks over standard double ones, but thats not a nessisary one.