The Tea Party, is not a political party. Tea Parties started as local demonstrations of people concerned about the direction of our country, and about the agenda that the Democrats in Washington DC were and are pushing. Tea Parties were born out of a frustration with the complete lack of conservative representation in the legislature and in the White House (as both chambers and the White House are controlled by Democrats). The name Tea Party is a reference to the Boston Tea Party, where colonial Americans demonstrated against Taxation Without Representation.
I have found it unfortunate since the very beginning that the term "Tea Party" shares the word "Party" with term "Political Party." The Tea Party is not a political Party. There is no "The Tea Party." It is independent groups of people who demonstrate for (largely) fiscally conservative principles. Some surely hold up signs for social issues, foreign policy issues and other things, but that doesn't seem to be the main thrust. The main thrust is fiscal. (I'd like to point out that the media likes to take pictures of the nut-jobbest people and signs they can find. I've personally seen them do it at a FairTax rally, where they found the one guy holding a non-tax-related sign. You can't believe that the pictures you see in the media are necessarily an accurate representation of what goes on at a Tea Party rally).
Unfortunately, many unscrupulous types have used this confusion arising from the word "Party" to their advantage, to try to use the name "Tea Party" for profit and or political damage. In Florida, for example, someone did actually register a political party named "The Tea Party." Some accuse Democrat Alan Grayson for doing this to split the conservative vote between the GOP (Republicans) and the Tea Party candidate. I don't think anyone has any proof of a conspiracy, but the net effect is a help to the Democrats (and Grayson).
Further, there are multiple separate national groups that use the Tea Party name. One is the Tea Party Express, a national bus tour. Another which gets national press is the Tea Party Patriots. There is a list of others on Wikipedia. These organizations are all separate from one another, and sometimes even endorse different candidates from one another. Further, the people who attend the rallies don't necessarily consider any one group or another to be their leadership. Tea Party rallies are often organized at the local level. They occur in large cities, and even in small towns. (I'm not saying that every single Tea Party rally is local. No, I don't have a percentage).
The aim of the Tea Party is _not_ to create a national political party. The aim is largely to reform the Republican Party. Tea Party attenders largely believe that the Republican Party failed them during the Bush years, increasing the size of government, and increasing the national debt. Tea Party-goers favor voting out RINOs (Republicans In Name Only), and replacing them with true fiscal conservatives who want to reverse the current trends of deficit spending and government increase.
Note that everything I say is a "by-and-large" assessment of Tea Party-goers. I don't want to hear "well not EVERY Tea Party-goer believes that, etc. I'm sure there's at least one who believes just about any side of any issue, and I'm sure that one has been written about in the press.
All that to say, it annoys me no end that even Fox News seems to get it wrong all the time by saying things like "Tea Party Candidate." when they should be saying something like, "Tea Party-endorsed Republican Candidate," or "Tea Party Favorite," (which they do say sometimes and is slightly less confusing).
In summary, the Tea Party is NOT a political party.
[btw: I tried to make this post understandable to those not necessarily familiar with American politics, hence some of the "obvious" (to Americans) stuff.]