I think it would be important for the success of PPC to get it into an exchange which allows direct fiat-to-PPC trades.
Vircurex was the only exchange that had something similar but depended on the VouchX system from Aurumxchange which is now closed. BTC-E has no USD/PPC and EUR/PPC currency pairs and it is a bit difficult to get fiat in there (although I’ve seen they have recently added Neteller).
I know there is a feature request to MtGox, but I am sure that the inclusion there is still some months away. They will first implement Litecoin (hopefully in July) and then surely evaluate their experience with altcoins until they accept others, so I don’t expect this to happen until at least September or October. So I think it would be a good idea to find a smaller exchange which could add PPC first.
One exchange I have looked at is The Rock Trading (https://www.therocktrading.com). They have LTC trading implemented already so they have experiences with altcoins. They have SEPA deposits without fees and some other interesting payment options. I am trying them out for now (with BTC) and if my experiences are good I will ask their support if they could add PPC. I think everyone interested to buy and sell PPC directly for fiat should then register there and support my request 
If you have another idea feel free to post.