I think first thing I'd do is drive it around, get it to do that, and as soon as it starts, put it in nuetral and see if it rolls to a stop unusually fast, indicating a brake hanging up.
If that's the case, walk around the car and feel the temp of each wheel. The one with the stuck brake will be much hotter than it's counterpart on the same axle. The front will generally be hotter than the rears.
If you can, let it roll to a stop without using the brakes at all, that will make the temp difference really stand out, if one is dragging, it'll be the only one really hot.
If that's not the case, does it seem to downshift when you stand on it? Or is it just laboring along in top gear, making no power? If you downshift it manually does it accelerate ok?