Finally, one I know for sure - Twelve- spotted Skimmer (Libellula pulchella)
Nice photos !
As for future identifications there are several good books for beginners.
try
Stokes Beginner's Guide to Dragonflies by Blair Nikula, Jackie Sones, Donald Stokes, and Lillian Stokes (Paperback - May 2002)
or
Life Size Damselflies & Dragonflies of Southern Ontario [Paperback]
Mike G. Peters (Author)
both available on Amazon
Whenever I find an insect I do not know I check out
http://bugguide.net/node/view/15740. It can be hard to find what you are looking for at first but finding things while browsing is half the fun !
Let us know how you make out on future adventures!