AirTran Airways A+ Rewards - Promo to join?

I started discussing the US Grand Slam promo with a coworker, and she mentioned that she never signed up for any FF programs because she never saw a point. She then mentioned that she travels about 3 times a year for vacations, and I suggested that she join. Her next flight is on AirTran, so I told her that I'd see if I could find any promos for her in regards to joining.

Any promos out there? Or, any referral bonuses?

Thanks!

http://tickets.airtran.com/LoginPromo.aspx?promo_key=FALLDBL2011

http://tickets.airtran.com/LoginPromo.aspx?promo_key=FALLDBL2011

They've had their tickets though, so that won't work for them, since it says they must book from September 15.

I believe it takes 4 points for a 1-way business class upgrade. After two round trips in the back they'll have enough points to upgrade one-way on their third flight. Good enough reason initself.