i don't know if it's open source or not. but the best media player i've found is Double Twist. I installed the app on the phone and the program on my pc. it syncs music, photos, podcast very similar to itunes. Sync Android, PSP, BlackBerry, Pre: doubleTwist with Amazon MP3 i believe is the website.
You have to use the menu button on your droid x and select the usb connection and then select mass media. That way double twist will recognize it. I've had the same problem. Unfortunately, double twist is too slow and video import is still a mystery to me. I've switched to isyncr which is faster and easier.
I just downloaded it and am using it now! Love it so far, but I see a delete button that is disabled...I'm trying to figure out how to remove songs from my droid that apparently came on it that I don't want... Since the delete button is disabled, this app isn't helping me there either...
Any suggestions? I tried doing it through my pc browser, but for some reason my pc is not recognizing my phone. I have even gone into the settings and selected Disk Drive...