PS3 owners might want to start warming up their clicking fingers, just to be on the safe side.
Blizzard has been saying since 2008 that of all its PC-centric franchises, Diablo made the most sense to port to consoles. Last November, we first saw hints that the developer was "exploring Diablo-related concepts for consoles," but precisely what that means is rather vague.
Now, though, there may be something (slightly) more concrete in the mix. A Joystiq reader noted a very interesting job listing on the Blizzard site - a job listing that really didn't mince words: "Senior Software Engineer, Console -- Playstation 3 Specialist." The position would be "responsible for overseeing Playstation 3 (PS3) architecture design as well as other PS3-specific game code development to maximize platform performance."
It's entirely possible that this job listing is nothing more than part of Blizzard's previously-mentioned explorations. After all, the Xbox 360 is relatively similar to a gaming PC, so a PC-centric developer like Blizzard might find the hardware easier to work with, while they would need someone experienced for the PS3 version.
On the other hand, this listing directly mentions that part of the Diablo III team is working with PS3-specific game code. So who knows? Either way, the PC is undoubtedly the primary platform of development for Diablo III, whereas any console version would be a port developed after the fact.
On the other, other hand, permit me to speculate a bit: It's all but certain that Diablo III will be tied in to Blizzard's Battle.net service in much the same way that StarCraft II was (for better or for worse). With Portal 2, Valve was able to bring the equally-crucial Steam and Steamworks to PS3 in a way that Microsoft's Xbox Live didn't allow.
Perhaps Blizzard could be considering the same thing - if the PS3 can run Steam over PSN, why can't it run Battle.net and let PS3 users and PC users play together? Of course, the question there is: Where does that leave Xbox 360 owners? It's unlikely that Microsoft would allow Blizzard to circumvent its Xbox Live service, but if D3 is being built around Battle.net 2, Blizzard probably wouldn't want to release a version without it. And a multiplayer-less Diablo III wouldn't be nearly as fun.
Of course, this is all just complete speculation. All we have here is a job listing for a project that may or may not ever materialize - because really, Blizzard can probably afford to hire people on projects that never see the light of day.