Earth2Tech has a roundup of biofuel startups that are working on turning algae into fuel. We can't yet know what will happen; Some of these companies might become huge in the next few years, or they might be left in the dust by new developments (solar energy below $1/watt and advances in battery or hypercapacitor technology, for example). Only the future will tell, but in the meantime, they are worth keeping an eye on.
The companies are: GreenFuel Technologies, Solazyme, Blue Marble Energy, Inventure Chemical, Solena, Live Fuels, Solix Biofuels, Aurora Biofuels, Aquaflow Binomics, Petro Sun, Bionavitas, Mighty Algae Biofuels, Bodega Algae, Seambiotic and Cellena. For more details, check out: ::15 Algae Startups Bringing Pond Scum to Fuel Tanks