How do I go about digging a drainage ditch in front of my garage door?

I have a 100+ ft gravel, 2 car wide driveway that slopes downward towards the house (garage, actually). When it rains or when snow melts (I am near Chicago), I get an aculation of water in front of the garage and some of it, depending on the amount of rainfall, ends up in the garage. What do I need to do to combat this problem? How deep do I dig the trench? How far past the garage do I need to dig? What materials am I going to need? Is there any way to fix this without buying the expensive iron "ditch" with the grate across the top of it? Any help is appreciated. The winters kill me the most as all of the ice from a slight thaw aculates directly in front of the garage.