The most commonly grown passionfruit here, Passiflora Caerulea, does have edible fruits, but they're rarely described as such because they're not used commercially, as their flavour is generally considered a bit nondescript.
The purple passionfruit available in the shops is usually P. Edulis or sometimes P. Quadrangularis (the Giant Granadilla).
I'm growing both of these outdoors this year. Started them off indoors in the New Year then put them outside in late April where they did absolutely nothing - like everything else in the garden - in the dull overcast May weather. However this recent hot spell seems to have got them going again, though I doubt now if they'll fruit this year. Mind you, if they even flower, the photos will be in the Gallery so fast... !
