You could use width / height for example. There's no "right" value, it depends on what you want to achieve.

There was a mildly relevant discussion on Slashdot: http://ask.slashdot.org/article.pl?sid=05/11/30/0048221

The second argument to gluPerspective is the aspect ratio for the projection, simplest way is to use the aspect ratio of your window.

You also need to take a step back :-)

In your MODELVIEW matrix, add a translation in the "z" axis of about -10 units. Now you should see your cube in perspective.

It sounds like something is backwards...

[local] $ ssh remote_host
[remote] $ xterm

The last line will display an xterm in your local computer. Your description sounds like you wish to display a window from your local computer in the remote computer, is that right? Also, ssh takes care of setting DISPLAY to the right value, you shouldn't need that.