The charts above are from the Gallup Poll. The most recent survey was done between January 21st and February 2nd of a national sample of 906 adults, with a 4 point margin of error.
The top chart shows that the desire for a third political party is higher than it's been since Gallup has been asking this question (October 2003). It currently stands at 62% (with 33% saying it's not needed).
The most support comes from Independents (70%) and Republicans (63%). Only 46% of Democrats agree.
NOTE -- This poll should be viewed as not serious. There are already more political parties on the left (Green Party) and the right (Libertarian Party and Constitution Party). It's easy to say another political party should be created, but it is doubtful that many people would actually join such a party.
What these people really want, in my opinion, is a party that agrees with them on everything. And that, regardless of your beliefs, is a near impossibility. The poll represents dissatisfaction with the current parties, but creation of new parties is unlikely to fix that.