Lots of great online resources for grasses (this forum is one), but if you really want to learn, I'd recommend getting a good book on ornamental grasses. I like both Rick Darke's Enyclopedia of Grasses and John Greenlee's Enyclopedia of Ornamental Grasses. Rick's is a bit more current on info.

Online, try some of the grass retailers:

Bluestem has a nice grass comparison chart
http://www.bluestem.ca/grass-comparison-chart.htm

Santa Rosa Gardens has an A to Z listing of grasses
http://www.santarosagardens.com/Ornamental-Grasses-and-Sedges-s/110.htm

High Country Gardens has some good info on grasses
http://www.highcountrygardens.com/ornamental-grasses/

The University of Minnesota has some really great research on cold hardy grasses
http://www.extension.umn.edu/distribution/horticulture/DG6411.html

NC State University has some info on grasses that may be more pertinent to your area
http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/ornamental_grass/scientific_names.html

Thank you!!