How can I have part of a texture map be transparent?...

For instance if I wanted to create a wall with holes in it. I want to map the texture onto a quad, but have some parts in the middle of the texture be transparent.

How can I do this?
Any help is much appreciated.

Thanks.

[ffish]

Look into alpha testing. If you build a texture with an alpha value, you can use an alpha test to mask out the values you don't want. Check out this demo by Leyder Dylan:
http://www.opengl.org/discussion_boards/ubb/Forum2/HTML/004351.html