"It was part of Tax Day protests held throughout the 1990s and earlier. By 2001, a custom had developed among some conservative activists of mailing tea bags to legislators and other officials as an act of symbolism."
"Perhaps the first "Tea Party" event on record was an event for Ron Paul dubbed "Boston TeaParty07" on December 16, 2007. This event included the throwing of boxes labeled "tea" and "IRS" among others, into the bay." Wikipedia http://en.wikipedia.org/wiki/Tea_Party_movement
Not "after Obama took office it prompted the rise of an entire new movement, the Tea Party" as you state.