A few days ago, the Pew Research Center released a fascinating report on shifts in party identification among various types of voters. A taste:

  Since 2004, identification with the Democratic Party has increased across all age groups. Four years ago, 47% of all voters identified with or leaned toward the Democratic Party, while 44% identified with or leaned toward the GOP. In surveys from October through March, Democrats held a 13-point party identification advantage (51% to 38%).
  Perhaps the most striking change since 2004 has come among voters born between 1956 and 1976 -- the members of Generation X and the later Baby Boomers. People in this age group tended to be more Republican during the 1990s, and the GOP still maintained a slight edge in partisan affiliation among Gen X and the late boomers in 2004 (47% identified with or leaned toward the GOP while 44% described themselves as Democrats or leaned Democratic).
  Currently, 51% of voters in this age group affiliate with the Democratic Party or lean Democratic compared with 39% who describe themselves as Republicans or lean toward the GOP. Thus voters in Gen X and the latter part of the Baby Boom -- the most Republican age cohort four years ago -- now are about as Democratic as are older age groups, the early Baby Boomers and the so-called Silent Generation.
  Still, the youngest voters -- the members of Generation Y, born in 1977 or later -- continue to stand out as the most Democratic age group. The Democrats' identification advantage among Gen Y voters, which was 13 points in 2004 (52% to 39%) has nearly doubled in the current presidential campaign to 24 points. The current generation of young voters, who came of age during the George W. Bush years, is leading the way in giving the Democrats a wide advantage in party identification, just as the previous generation of young people who grew up in the Reagan years -- Generation X -- fueled the Republican surge of the mid-1990's.

Thanks to Andrew Sullivan for the link.