As other people have "voted" ... it seems broken here too.
Had the twenty eleven theme enabled and not a single functionality from the eShop plugin showed up at the front end (on my product page)
I then switched to the twenty ten theme and I got some functionality (got some product descriptions, link to shipping rates etc) but no BUY NOW button.
Is eShop incompatible with 3.3.1 ? is there an update in the pipeline ?