Yes, Smith was working on a inspired translation of the King James Version of the Bible.  
 
The foot notes of the LDS printed King James Version of the Holy Bible has the Joseph Smith Translation in it.  
 
There is also an appendix for later portions as well as excerpts in the Pearl of Great Price from parts of Matthew and Genesis.  
 
All of these are found at http://lds.org/scriptures?lang=eng 
 
Overwhelmingly the JST is there to fix minor errors, though in some parts lost verses and passages are revealed again to add clarify and bring the KJV more in line with the lost original manuscripts.  
 
This was all done by the power of the Holy Ghost.