Sources

NCBI molecular databases

BoLD (BarCode of Life Database)

ITIS and the 2008-9 Catalogue of Life

BHL Literature

GBIF-mobilized occurrence data (synthesized to distinct name not all 170 million points)

EoL Species pages

Redlist, GROMS, RAMSAR, BIRDLIFE or other conservation related indices

• particularly if data publicizing enables discovery of content NOT previously accessible.

Scratchpad, LifeDesk indices

Tropicos

Exemplar online Flora and Fauna

• (Harvard and MOBOT have many and are partners)

Fauna Europaea

CAB Direct

• I am writing the Terms of Reference right now for a uBio project to extract taxon names from 1.8 million bibliographic citations from CAB Direct, a database maintained by CABI in the UK. It will provide millions of links by names to bibliographic resources located here:
  http://www.cababstractsplus.org/google/abstract.asp?AcNo=19980803431