Maptools/Gimp Help

[Cool as a Cucumber]

Alright so, I am trying to make some textures/tiles for maptools, and I have so far done the first half right, I made the LOOK like textures/tiles. Now the only problem is, each and every one of them has a white or black background. So in order to correct that, I downloaded GIMP. Now the NEW issue is, I read the manuel to gimp, followed the instructions, and yet still cannot make the textures/tiles backgrounds transparent (or topdown or w/e it's called)

So please, help. How do I make things backgrounds transparent on Gimp? (The simpler you can make it sound, the better. :p)

File -> New

- Advanced Options
Fill with: Transparency

Set the image size how you want it to be.

Hit OK, then paste the image.

Fuzzy Select Tool (hit U on your keyboard), select the white/black area, hit your delete key.

Save as PNG or GIF.

I'm not sure if there's a faster way to do it, I usually use PaintNET for simple stuff.