Richard Yot provides a great look at the new retopology features in the latest release of Modo to Re-Topologize an Organic Model (as well as some standard tools) developing a fast and efficient workflow.
Recently, Luxology has shipped Modo 601 with some huge additions, including a focused environment for re-topology modeling which combines a specialized user interface with new tools that make it easier than ever to create clean geometry on top of a background mesh. Check out the features of modo 601 here.
