That's how many dots you have on the screen.
1024 horizontally and 768 vertically. It makes a grid. The higher the number the smaller the dots. The smaller the dots the smaller the text and graphics appear, but everything also becomes sharper. 1024x768 is pretty common and relatively standard on laptops, desktop monitors usually go much higher..
Quote 03-19-08
"Yes, we must, indeed, all hang together, or most assuredly we shall all hang separately." ~Benjamin Franklin to John Hancock