I also bought from Gamestop and chose Express delivery, but where do you find the tracking number?
In the email check out the link for the tracking (above the table). The link won't work, but if you look in the address of the link it has your tracking number Copy and paste it into the box in the link.
Just got all my downloads on the go now Motorstorm RC, Escape Plan, Super Stardust, Tales from Space, then a load of demos, the free games and the facebook and twitter app
I also got the PS3 motorstorm version downloading so can play that straight away