The world of Skyrim can be a cold, unforgiving place--especially since so much of it is packed with snow. But you can warm the place up a bit with Hearthfire, which hits PCs today. It's been on the Xbox 360 for 30 days, which means the exclusivity window is over and PC owners can start building.
Or rather, they can start building with official tools. Mods let you build houses and adopt kids already, so Hearthfire is really more targeted at the player who wants the officially Bethesda-created versions of those features. You can make a house, outfit it with different types of rooms, find your own crafting materials, and then take in some kids to occupy the place while you're out adventuring. It costs $4.99 and is available through Steam.
As for the PlayStation 3, that's a different story. The console is already way behind on getting the Dawnguard DLC working. Hearthfire is a bit less ambitious in scope and may be easier to port, but at this rate it might be a while before you can warm your cockles on Sony's platform.