Anyone who has a clue to the makeup of the Tea Parties would know they aren't monolithic. Indeed, there are many libertarians, many conservatives, some moderates, and even a few liberals.
I don't think there is anyone that 'speaks' for the tea parties, as they differ not only from state-to-state, but within states.
I 'speak' for IL tea party, I'm on the state commission. We are a blue state, trust me, Durbin will win in 2012, barring a miracle. Burris will vote for obamacare, regardless of his pledges about public option. It's the Chicago Way.
So where are the commonalities between a state like IL and one like OK? Those that join in some activity of any level, wants a better US. They are concerned about the Constitution, taxes, future.
Are there racists within tea parties? Without a doubt. Then again, there are within DNC and GOP. There are within the Greens and Communists parties too. However there aren't any that I know of in leadership positions. Most of those subscribing to the ideology want lower taxes, less federal government in areas that should be state level or even lower. They want cleaner state government, (especially in IL).