According to Motorola's discussion of DLNA on their website (I'm sorry that I didn't record the URL when I read this information), Media Share is a legitimate and simplified version of the more advanced DLNA app. At least for the Droid X, when you hook up to your PC for the first time you will get an offer on the Droid to launch the Media Share app, which is how you want to get started on file transfers and the like.
I did this and on at least the Droid X the instructions are easy to follow. At one point you will see a screen that says "Enable Memory Card Management" and what that screen is asking you to do (it's confusing) is choose "Charge Only" (I think - once I made the right choice it went to the next screen). The interface is a little clumsy but it certainly works. I easily transferred a large number of photos from the Droid to the PC (a new Falcon running 7 64-bit) with no hassle, and could have easily transferred photos the other way.
As a side note, it looks to me that you could possibly screw a few things up on your Droid with this protocol, because when you go into the Windows directory map, it gives you access to everything on your memory card.
Anyway, Media Share is a pre-installed Motorola app, it is legit, and it does work.