If you don't know what a "push poll" is it is Wikipedia has a good explanation. A push poll pretends to be a poll (what is your party affiliation, do you plan on voiting) but slips in some not so subtle boosterism for a candidate or against another. In this case the poll asks "are you more likely to vote for a tax cutter like Huckabee who is also totally awesome, or a tax raiser like Thompson who drinks the blood of small children?" (the tax part of that was in the call, anyway).
It is dishonest because the first neutral Q&A portion causes people to treat the later information as neutral (at least at first). It is nefarious because the first set of neutral questions allows the push poller to tailor the rest of the message to the particular voter. In this case it is bullshit as well because Huck is a big tax raiser and Fred isn't. [The Huckabee line is that he cut taxes 70 times and raised them only 20. This is truthy, he cut taxes a nickel 70 times and raised them a dollar 20 times.]
I'm a free speech guy and I think this kind of thing should be completely legal. I think the voters should also brutally punish the sponsoring campaigns. In this case there is no doubt these are Huck's guys. So punish away.