Doug, I make it a point to tell all my clients that if someone thinks your shit is worth booting / sharing / etc. at least that's a bit of a compliment - you're getting noticed!
You can (and should) send cease & desist letters to the sites - you should also activate Google Alerts (free) so you don't have to do dailiy searches.
"MAY YOU LIVE AS LONG AS YOU WANT, BUT NEVER WANT AS LONG AS YOU LIVE. MAY YOU LIVE TO BE 100, & ME 100 BUT MINUS A DAY, SO THAT I'LL KNOW THAT NICE PEOPLE LIKE YOU, HAVE PASSED MY WAY. AND REMEMBER, WHEN FRANKIE CROCKER ISN'T ON YOUR RADIO, YOUR RADIO JUST ISN'T REALLY ON."