The short answer is "not much."
Their official web site consists of three paragraphs. For example, this explains how they started:
Well, we started in Nov 1988 with a benefit for the striking Nikolai door workers in Springfield, Oregon... We built a giant electrical motorized penis that shot salvos of dove liquid into the audience (still have it in our storage space)... Later we were into mad scientist rock, where we had ideas for crazy inventions which we combined with rock and roll - you know, "kids after the show go build your own shoe tree chariot, here are the blue prints!" *
Awesome. That's about all that's on their site, except a list of shows (I guess they still play live), and insistence that their "flyin saucer seems headed for the sun again with our new ultra mega jam 'Spin the Fuck Around' - the Hippies really get their stanky on to it, bisnatch. See you at the bank!" I haven't heard it on the radio yet, but I'm looking forward to it; these guys are obviously much cooler than the "swing revival" that popularized them.
* I don't feel bad plagarising this paragraph, or the picture above, because the bottom of the site says "No artwork or music may be used with express written permission by The Cherry Poppin' Daddies." I guess that means that without written permission, it can be used. Sweet.