Can someone recommend me a good MoCap software ?

THis one: http://www.ipisoft.com/

sounds good, but...
The BVH file generated by this one is not compatible with SL.

The right lag is ignored and also the leg gone uppon the head and stay stopped all the time.

Im looking for a good Mocap softeare like thtis, that I can attach some web cams to capture movements and then create compatible BVH files to upload to SL

Can someone suggest me one ? Yes, can be a paid and expensive software if necessary.

I don't know why you think the BVH from this ssytem is incompatable. I downloaded the sample data and was quickly able to massage it around to where it uploaded to SL with no problem. No problem other than it looked worse than some of the worst hand animated animations I have seen.

If you are asking these questions and looking a a product like this you are not really ready for a recommendation on a system. And what you will need is a system, hardware and software together to do MoCap.

Some sites that may help you get some of the anwsers you need:
http://www.naturalpoint.com/optitrack/
http://www.metamotion.com/
http://www.motion-capture-system.com/
http://www.xsens.com/en/general/mvn
http://www.organicmotion.com/
http://phasespace.com/

As you can see there are many choices, none are inexpensive and you need to know what types of motion you are planning to capture as that will have an impact on which system will work best for you.

I sent you the uploaded ipSoft animation in world.