erm. MS's cable is just a crossover cable. It crosses two pairs of wires compared to a regular straight through ethernet cable. That's it.
Think of it like two wires for incoming, and two for outgoing. Only 4 wires are needed in the Cat5e cable in a 10/100 network- pins 1, 2, 3, and 6. In a crossover situation, the two pairs are switched so that one ends incoming comes from the other's outgoing, and so on.
So to answer your question, no you can't use a regular (straight through) cable if you're connecting 1 xbox directly to another...but you can (and should) use one if you connect each xbox to a hub/switch/router