You want to claim your bags on the lower level of T2. You can catch the CTA by going down to the Pedestrian tunnel near exits 2B or 2D once you claim your bag. (See map linked)
http://www.ohare.com/PDF/PassengerIn...20Acce%20E.pdf
Here's an excellent link regarding your CTA question.
http://www.transitchicago.com/riding_cta/airports.aspx