Is it true the story was based on a manga?
Yes, Hayao Miyazaki originally created a 3 part manga for the magazine Model Graphix. The movie was adapted from the manga.
Where can I buy goodies related to the film?
Please visit the Shopping Guide section.
Does Porco Rosso and Gina end up together?
They have a good response for this question at Nausicaa.net. I wasn't really sure myself when I saw the movie. In the film during their last meeting, Porco Rosso said good-bye and sorry to Gina, perhaps as a way to turn down her love. Grown-up Fio also says that she became good friends with Gina and visits Hotel Adriano every summer, but never saw Porco Rosso again. If Porco Rosso was with Gina, Fio should see him again. However, another interpetation can be taken by assuming Porco Rosso did turn back into a human at the end of the movie. He apologized to Gina and said good-bye at first because he thought he still didn't want to be human. But after the kiss from Fio, and the realization of Gina's love sinks in, he decides humanity is worth it. So, he goes back to Gina in his human form, and becomes Marco Paggot once more. When Fio returns to Hotel Adriano each summer, she doesn't see Porco Rosso again but sees Marco Paggot, who stays human. I personally prefer the happy ending. ^.~ It is kind of depressing if in the end, the message is humanity is not worth it. >.<