icallug, you, like someone else i recently responded to, worry too much. you don't necessarily have to say, "will you go out with me?" simply plan a date and ask her, "hey, you want to go do this with me?" if you play the date right, you'll automatically pull her in as your girlfriend. it may even take a few dates, but hey, if it works...
another little bit of advice: don't do something like a movie. they seem like a great date, but at first it's best to do something more active. for example, if you like bowling, try that. or, depending on where you live, maybe you could go on a hike with her.