Actually, the disc drive itself should tell you, in writing or a symbol on the flap-- Mine says "compact disc rewritable" and "dvd rom." I hypothesize that if your drive can burn DVDs, it'll say "dvd rom rewriteable." And if it doesn't tell you, oh well. It takes like, 5 seconds to check. ^_^

(another idea is to see if there is DVD burning software in your start menu, although that is not a fool-proof indicator.)