DTP Tools has released Layer Groups 2.0 plug-in (http://www.dtptools.com/layergroups), which more than doubles the feature set of the previous version. The plug-in is Adobe Creative Suite 5 ready.
Layer Groups 2.0 adds: listing of objects in the layer on current spread; listing of objects in the layer in the document; and importing layers including structure and content from other documents. Also, users can enjoy the listing and naming of objects within a layer introduced in CS5 in any InDesign version from CS up with additional settings filtering objects for spread or document.
Upgrades to Layer Groups 2.0 from any previous version of Layer Groups and InDesign is free. For new users the cost is US$40 per license. A demo is available for download.