The polls conducted during the mid-term elections showed some interesting results about the pollsters themselves. In particular, Rasmussen, the most prolific of the pollsters fared the worst. Of the ten top polling firms, Rasmussen was not only the least accurate in its projections during the last three weeks of the campaign, it was also the second most biased in its assessments, most of which were done under contract with Fox. Most accurate and least biased were the Qnnipiac polls.
Unfortunately, it seems that the mix of a low cost approach to polling plus a strong political bias by the owner have produced a poor mix if your interest is accurate results. The linked story is very interesting and provides some good insight.