[mesocosm]

Definitely a great idea ...
Apologies for any redundancy with kmk2307's excellent list.

(General Classification)
http://www.botany.hawaii.edu/reefalgae/default.htm

(General Classification)
http://www.mbari.org/staff/conn/bota...mark/index.htm

(General Classification)
http://www.algaebase.org/

(Coralline Alga Classification)
http://www.botany.uwc.ac.za/clines/

(General Classification)
http://www.biology.plymouth.ac.uk/Re...Phycology.html

(General Classification)
http://www.sonoma.edu/biology/algae/algae.html

(One of John Rice's picture pages with Macroalgae Links)
http://www.globaldialog.com/~jrice/a...ae_gallery.htm