USAToday has an excellent recap of the changing marketing effort to the 49+ crowd. Since I've been repeatedly blasted on this board for saying much the same thing I thought it might put better words to my argument - and a bit of vindication. While the article applies in large part to TV the same message seems relevant to radio.
http://www.usatoday.com/money/advertising/2010-11-15-babyboomers-spending_N.htm
http://www.usatoday.com/money/advertising/2010-11-15-babyboomers-spending_N.htm