Moksha is realizing oneself to be atma and atma to be Brahman. The Jiva is already liberated in its true nature - thus realizing the true nature of oneself (jiva) is liberation. Thus, one can be liberated even though one is wearing a body. This is called jivanmukti (getting liberated even while "living" in a body). Videha mukti is achieved eventually, after jiva leaves the body.
Also See :
Also See :