Go to
http://imageshack.us you'll see this:
Click "Browse":
Select the file you want to upload and hit "Open":
Then click "Host It":
Now copy everything in one of the boxes circled in red and paste it where you want the image to appear on the forum:
Or you an click the image in the blue box and copy the whole address from the address bar and paste it into an e-mail or IRC or whatever.
