apple sell a vga to dvi thing exactly for this purpose, they ship with all mac mini's, and should have come with your apple monitor. Otherwise they are about $15 from the apple store.
$15 for a vga/dvi adapter? Guess you gotta pay to get that shiny bevel. Most video cards come with vga/dvi adapters as an accessory. You could probably get one for free from someone who's recently purchased a newer video card.