Well, just to make it easier than looking through the whole FAQ...
If the picture is already on the internet, simply copy the location of the image (right-click it and selct 'Copy Image Location' in Mozilla/Netscape or something similar to that in Internet Explorer) and then paste (Ctrl+V) the location into your post, between tags like these:
If the picture is currently on your hard drive, you'll need to put it on the internet with a hosting service. Assuming you don't own your own webpage, I suggest signing up at http://www.photobucket.com
(it's free) and following the instructions there. You can also use another site, http://www.imageshack.us
in the same way without having to sign up, but sometimes the locations there will get corrupted when you edit your post, and the images will be broken, like this one:
Hope this helps.
And Slackit, he wouldn't be so busy if you stopped making him go clothes-shopping with you and buying you delicious German chocolates.