This ad, from Crossroads Grassroots Policy Services, is long but extremely effective, in my humble opinion:
Some might find it jumps around a bit, but the theme is pretty clear: compared to private-sector workers, unionized public-sector workers get a pretty sweet deal once their benefits and pensions are thrown in with their salaries. Those high salaries fund union dues; those dues fund the organizations that keep Democratic lawmakers in power (or try to); the lawmakers then make sure that the public sector pay, benefits and pensions remain high and untouchable. That is what the recent fights in state capitols are about, and it is clear whose side President Obama is on.