There is no way that is true. Unless they gain a huge majority and then win the White House the only thing they will be able to do is create gridlock (which they already can do) and not renew the tax cuts (which might happen even with a GOP congress).
I just don't think untrue fear-mongering is the right tactic. There are lots of other things the Donks can and will do that are both fearsome, possible and true.
First, they don't have to do anything to increase taxes. All they've gotta do is let the Bush tax cuts expire in 08, as they're scheduled to do.
Second, I predict that the Dems will spend the next several years paying Big Labor off for their support. By the time they're done, the US economy will be a Mexican or EU style disaster. They are already trying to help Big Labor unionize Wal-Mart.
Big Labor destroys every industry it touches. Look at the railroads, the steel industry, Big 3 autos, textiles, furniture, and manufacturing in general. Even the education system.