I am wondering whats the difference between BVH and just animating a figure yourself with the frames in the poser platette?? I was looking into doing some live motion capture but not sure if its possible I saw some poses in the market that someone said they did them via live motion capture? any ideas?

Well, time being one major difference. If the BVH file you have does the same thing you were planning on animating ANYWAYS, why not save yourself the time and incorporate the BVH file? If you animate it yourself, you can be assured it'll work with your figure because you will be the one paying attention to what goes where. BVH files will lay out the general framework, it's up to you to go through and fix anything wrong (legs flying off in different directions, hands going through bodies or clothing, etc...). I guess it just boils down to whether or not you want to spend the time doing it yourself or from someone else's handywork.