i have 2 questions about this topic!!!

1. how can i put some mp3 that i have on a dvd to my hdd?? is there any way to "copy" them to my hdd??

2. When i have a CDRW with some songs (20 more or less...) how can i rip them to my hdd to hear them while i´m playing? i mean obviously this isn´t an original disc soth MS dashboad doesn´t recognize it and it says something like "your disc is not an allowed or authorized version" or something like that

You need to checout Xbox Soundtrack manager which can be found in the Tools section on here just go there and search for it.

Or you can put it on your computer and FTP it over.