I would think that the basic functionality would work. You could move the cursor and click. But the more advanced features that require an Apple driver and / or software wouldn't work unless it was provided by Apple.
If you ever decide to go Linux (in my friend's experience Ubuntu) you can take advantage of the gestures feature. The std trackpads support three finger scrolling already in the std build. I love this feature in my ubuntu laptop and am looking forward to all the other gestures when I get a Mac.
For Windows it will work on your Dell XPS. You need to install Apples Windows Driver. You can configure that driver with the Magic Trackpad Control Panel for Windows.