Sergg, The best way I've found to transfer files to my xbox is via a standard memory card. I bought a Mad Cats version for around $20. I was going to need one anyway, so I bought it.
How does one transfer games to his memory card from his PC? Well you plug your xbox controller into your PC with the memory card installed. Funny, you say? It is funny, but the xbox controller is detected as a USB device as is the card. With the drivers that come with the Action Replay software (free update), you're off to the races.
How does one connect his xbox controller to his PC? well, you gotta "hack" it together. Meaning take out your wire cutters and "hack" into the cables my friend. Then you mate a male USB connector to a hacked up xbox break away cable and then connect your controller to that. End Result: xbox controller & memory card plugged into PC via USB connector.
Here is a pic of how you wire it (notice the yellow wire goes nowhere). Good Luck.
P.S. The motivation behind this thread is great, but I think it should be updated to mention LTools as it would have saved me the agrivation of trying to install UDE by hand.