I did a little reasearch into this for you, and there's nothing out there I found that'll read in the .MA files directly from Maya. But, you can download scripts (like Max's Maxscript) that'll allow you to export .OBJs from Maya, which can then be imported into Max. Unfortunately, this means that you need both Max and Maya (a very expensive propostion).
Thought that I found something with PolyTrans for Maya and PolyTrans for Max, but neither of those are standalone programs... they both need either Max or Maya to operate. But PolyTrans for Maya (with Maya itself) would allow you to read in a .MA file, and then export it to .3ds for importing into Max with minimal additional work. But that's also about the cost of a good bookshelf stereo right there.
Your best bet would be to get the .OBJ script exporter for Maya, and unless you have Maya yourself, ask a bud with it if they could import those .MA files and then export it using the .OBJ script. That'll give you a mesh to work with (though I don't know if you're going to lose UV mapping).
There were two guys out there though that someone could approach possibly to get the ability you're looking for in the community. One may be chisofborg from assimsoft. He might be able to add that into his MS3D plugin set. Although one problem there is simply that MS3D just isn't going to be easily capable of handling the kinds of polys that you're going to find on average with Maya. (He really needs to re-write a copy of those plugins for us guys with Max. )
The other guy would be the author of Ultimate Unwrap. I remember a good while back he did a plugin that'll handle .MOD files with Ultimate Unwrap... maybe he could write one to handle .MA as well. If he could do that, it'll be a considerably less expensive proposition than PolyTrans and Maya.