Which is where things got muddy. After it hit the app store, one of the original developers of XPilot told us he feels adamantly that we're betraying the spirit of the GPL by charging for the app (hopefully he'll chime in with a comment below; I'll leave him anonymous for now to avoid further stepping on toes).
That left us in a terrible spot. We'd thought we were contributing to the community and legacy of this game by reviving it, not stealing from them by charging for it — and didn't think $2.99 was unreasonable (and, again, the source is available for free from our page). It never occurred to us that one of the original creators would feel that we were betraying their contribution. We've discussed the philosophical fine points of free-as-in-speech vs. free-as-in-freedom with him, and have suggested a number of remedies — such as reducing the price (it's now $1.99), profit-sharing with previous contributors, making the game free at some point in the future (once we'd at least recouped our costs), or going "freemium" (offering a fully-functional free version plus a paid version with enhancements we added ourselves, with both GPLed of course). But in each case, the bottom line is that this developer feels the app should be free-as-in-beer period, and anything less is a sleazy betrayal of anybody that made contributions under that license. Which is a shame, because we deeply respect his work on this game and would love for him to be on board with the port — but at the same time this was months' worth of work and we honestly believe we're going about this in a reasonable way.
Obviously one of us has a non-mainstream understanding of open source ethos, but it's become clear we can't come to a consensus on which of us it is, and whether the "spirit of the GPL" allows selling GPLed software (especially when one wasn't the original creator of the software but a more recent contributor). The only way to determine that, it seems, is to poll the open source community itself.
We're determined to do the right thing by the GPL and the community. So here's our plan: we'd like anybody with an opinion on this to vote, and if the community feels that ethically this should be free-as-in-beer, we'll fix it by making it free, end of story. In order to make the vote clear and transparent to all participants, we'll use twitter. Remember, we're not talking about whether it's practical to base a business on GPLed software, nor the best business model for doing so, and certainly not whether the source must be distributed for free (obviously it must be), but just whether charging the binary version of an enhanced/ported version of a GPLed app (while releasing the corresponding source for free) is an ethically defensible thing to do.
If you feel that, ethically, any GPLed app must be given away for $0, include "#xpilot #freeasinbeer" in a tweet.
If you believe a binary version of a GPLed app may be sold with a clear conscience (as long as the source is distributed free of charge), include "#xpilot #freeasinspeech" in a tweet.
We'll count the tweets from unique accounts in one week and behave accordingly."