transferring from terminal 2 to terminal 3 at Beijing Airport

I arrive 9 Aug 2011 on Delta 617 at terminal 2 at 23:20
and depart 10 Aug on S7 516 from terminal 3 at 2:20

This a 3 hour layover.

What is the best way to get from T2 to T3
I do not have a Chinese visa.

Thanks