Raylight Games has released XrayUnwrap, its formerly 3ds Max-only UV umapping toolset, for Maya.
The software provides a streamlined set of tools for UV work directly within Maya, including the option to select edges on the mesh being unwrapped and see the UV layout update in real time.
Xrayunwrap 1.5.6 for Maya is available for Maya 2008 and above. It costs €12.99 (around $18). You can find video demos showing off the feature set in more detail via the link below.