I was reading my local newspaper online and they had this as an ad: FollowYourMoney.org I perused it a bit and it lists a bunch of companies and the amounts and percentages that the companies give to Democrats and Republicans.
Clear Channel which controls the most radio stations in the US:
GE (General Electric) which owns NBC:
Disney which owns ABC:
Viacom which owns CBS:
Time Warner which owns CNN:
News Corp which owns Fox News: