As others have said, regional Linux magazines (I think I see 2 magazines when I stop by my local book store), general Linux news sites and forums. I mentioned LinuxQuestions.org the other day, as someone has mentioned it in the past (
@Linux-SWAT was that you, in the Slackware area?) But it had been awhile when I last checked. I don't want to bring it up since I am only a lurker, and don't want to be mistaken for a spammer. Although distro specific forums may be ok I think the target should be places for enthusiasts.
Additionally, anywhere that people into technology with an open mind or different take on things gather. I was thinking 2600 and such, but I think you have to have a subscription to advertise in 2600. Since the magazine consists of reader articles, maybe ED or one of the people that works more behind the scenes can throw together something about what got us this far. It is only a quarterly magazine, so that will take time to pay off.
There are a bunch of gaming and retro gaming forums where I don't think it would hurt to mention it, but I am drawing a black on names right now. I will try to find some of the ones I used to check out and bring a few names back.
Unfortunately, very few of the places I frequent would be interested in the Pyra.