Microbial Genomes resource presents public data from prokaryotic genome sequencing projects. Prokaryotes are the earliest forms of life, appearing on earth 4 billion years ago. The Prokaryotes include the Archaea, which include inhabitants of some of the most extreme environments on the planet, and the Bacteria, which include both important pathogens and producers of fermented food, antibiotics, and vitamins.
Access to Refseq, annotation tools, data submission and others. Good start for beginner.