Take a good look at these sites:
http://www.okino.com/conv/conv.htm?0 - this site has a converter for Maya, XSI, 3ds Max and more.
http://web.axelero.hu/karpo/ - this site offers software that converts geometry to and from over 500 formats, some with skining and animation, some without it.
I also have attached an image of a link that was on this site (in this thread). I went to the site and just by some strange conicidence, it had a converter called PolyTrans (For Maya, 3ds Max, and XSI as separate plugins), plus it converts geometry, skinning, bones animation, .bvh motion capture, to and from DirectX, and a bunch of other formats (I believe there was FBX, Collada, and many more). See the link called "okino", that's where I heard about this converter. The other converter looks great too, but I couldn't find collada on the list of supported formats.
Happy to help!