How do you select an entire UV island on a mesh by selecting a piece of the desired island? Similar to the Ctrl+L for selecting all connecting geometry, only selecting all geometry within seams.
I.E. select a vertex within an island.
And hit some hot-key to extend the selection to the marked seams.
I use this feature all the time in 3ds Max, so I can unwrap a piece at a time. It would be a huge timesaver to be able to do this in Blender as well.