Having seen people working on high-poly models and needing to select sections of vertices (e.g. to paint weights or assign wrap deformers), I noticed how slow that can be.
I therefore created this tool to allow selecting vertices via selecting an outline of edges and then a vertex within them to select every vertex in that region.

Usage: Just click the shelf-button you made (or source the file by other means), select some edges (or have them selected before choosing the tool), press enter, and select the starting vertex.

Tested in Maya6.5 and 7.0 on windows, but should work as-is in all os's/most versions.