Uh-huh, think I'm with the program now.

In part 4 of the Cartoon Guy tutes, Kurt does a trick where he sets the background colour to be the same as the floor.

So, am I correct in guessing that you'd like to be able to post the images here, without the black border appearing?

If so, just do the following.

1) In the panel that you'll use for rendering, go to View->SelectCamera
2) Open the attribute editor if not already open
3) Scroll down and open up the Environment tab
4) Click the Background Color swatch
5) Change the HLS box to RGB
6) Change the 0 to 1 box to 0 to 255
7) Enter in these values R-237, G-238, B-243 if you'll be posting the image on a (simplymaya color) blue background, or 255, 255, 255 if it's to be on a white background.

Simon.

Here's the result: