Its a group of conservatives, they aren't a 'real' party, they are a subset of the Republican party (though the members of the Tea Party don't seem to like that).
The first 'Tea Parties' were started for Libertarians like Ron Paul, who want to abolish income taxes and greatly reduce the Federal governments power. After Obama was elected, they were sort of taken over by Glenn Beck and promoted as something a bit different.
The basic ideologies of the Tea Party is - less taxes/simplified tax code. They want a flat tax. They want to ban gay marriage. They want to promote Christianity in the US. They want to ban abortion. They are generally against comprehensive sex education and want to focus on abstinence only education. They promote gun ownership. As a general theme, they really hate "progressives" and most of their speeches revolve around how Obama is a socialist, communist, marxist, maoist, progressive, baby murdering Kenyan Muslim.