Air America's largest advertising account is Walgreens. You can email their customer relations departmrnt at: Consumer.Relations@walgreens.com
As I understand it, the corporate sponsors were buying time on the stations, not neccessarily as an ideological support for the programming.
Still it is funny that Air America spends all its time railing against big business, corporate greed, the high price of pharmaceuticals, etc. Yet their big sponsor is the largest drug store that has ever existed in the history of the world.
Meanwhile, Rush Limbaugh is supposedly the tool of "rich Billionaires" (Al Gore's exact phrase), and his sponsors are mostly Ma and Pa operations like Snapple, Hooked On Phonics, Select Comfort, The Mosquito Magnet, etc. At least, they start as Ma & Pa operations before the Limbaugh advertising makes them enormously successful.