Geranium

Glendale Geraniums
Large collection of photos plus a discussion forum.
http://www.glendalegeraniums.co.uk/

Hardy Geraniums
Home gardener in Ireland enthuses about her favorite class of perennials in this article filled with photos and information about the various species and cultivars.
http://www.esatclear.ie/~emal/geran.html

Hardy Geraniums
Devoted to information about the genus Geranium (Cranesbill). Based on the NCCPG National Collection belonging to Andrew Norton. Features discussion forum, images, and reference list of cultivar names.
http://www.hardygeraniums.com/

In Search of the True Geraniums
Article from Sunset Magazine provides some background and cultural information, and descriptions of recommended species and cultivars.
http://www.findarticles.com/p/articles/mi_m1216/is_n3_v200/ai_20463592

Rob's Plants: Hardy Geraniums
Pennsylvania gardener compares the leaf shapes and flower forms of the geraniums in his garden, and offers a few cultural tips.
http://www.robsplants.com/plants/geranium.php