I have cube maps in lat/long format, and i need to convert them to Horizontal/Vertical Cross, and individual cross images, is there an utility to do that?
I assume your source image is in equirectangular projection. You might try PTStitcher, part of the Panorama Tools package. It's designed to be controlled via script files, but there's a batch file located here called "Pano2Faces.bat" which is designed to simplify the use of PTStitcher to do an equirectangular-to-rectilinear conversion (although it probably won't work out-of-the-box on any version of Windows more recent than XP).
You can probably find a more user-friendly option somewhere on this page.
The tool we use for this is HDR Shop located here. http://ict.debevec.org/~debevec/HDRShop/
Version 1 of it is free. The option to use is "Panoramic Transformation". I can't say that this is the easiest tool to use in the world but its what we do.