From 3d.io is a plugin for 3dsMax and Maya that allows users to extract UV maps to be used best with Mari, Zbrush and Mudbox. It preserves user created UV seams and is user friendly. It can instantly create a rough unwrap if you need to bust out prototypes fast, or it can give you a good place to start from. A huge advantage of this plugin is that it saves a lot of time and helps create stretch-free uv maps. Check out the Unwrella website, and be sure to give it a try!