You'll need a computer, of course. Since you're reading this, I'll just assume you have one already.
If you already have Photoshop or a similar image editing package, discount this step entirely. However, if you don't,then you'll need to download a package off the internet. MS paint is NOT good enough for what we want. I suggets getting paint.NET. It's one of the best packages on the market,and it's totally free. You can download it at http://www.getpaint.net/
A printer is a very important part of the process. If you don't own one, there is almost always usable computers and printers at your local library. You'll of course also need some printer paper as well.
If you own or have acess to a laminator machine, then you'll be able to make your maps last significantly longer. If you don't, though, it's not a big problem.