iPad for displaying and ordering photos at an onsite multi day event

[CrescentiPhoto]

Hey All,
Hopefully someone can help me out there with this one. I shoot indoor sporting events during competitions and throughout the days that the events are going on, people can come and browse the photos that were shot and order them from me.

I am trying to find something that will make my life easy with an iPad that will allow people to browse the photos, add them to a cart and either pay us cash/check or enter a credit card right there and then. The photos would NOT be printed onsite, but sent to the customer a week later via a printing house. I will have a small laserjet there to also print up receipts for the customer too.

I do have a smugmug account, but during these events, I shoot pretty heavy and the bandwidth to send to smugmug isn't fast enough...

Any thoughts?

Thanks!
Steve