Another post from DeltaTwoForce says the mod is now working in multiplayer, too, so you can build your new PC with a friend.

This Minecraft mod lets you build an actual, functioning PC, then play Doom on it You order your (virtual) PC parts from a satellite flying overhead ...

Whatever it is you do (and really, I want to know), you can now add "play Doom" to the list, because with the help of a new mod, retro PC gaming has come to Minecraft.