Technically, it can be done on most home computers these days. You think we 3D artists use supercomputers? Nope. Mega-renderfarms, maybe, but the computers themselves are off the shelf stuff. Surprised? Shouldn't be. But I get a good laugh everytime I hear someone brag about some franken-puter they built thinking they "need" it for high end graphics.
Then add a copy of Alias' Maya for modelling, Photoshop for the textures and shaders, and either render in Maya or a seperate renderer like Pixar's Renderman. Of course, anyone can just go buy the hardware and software. It takes an artist to get your stuff looking good.
Render time? Depends how complex and how big. A few minutes to over an hour a frame, again depending. And scenes are also rendered in layers, much like Photoshop's layers. The actual character, shadow layer, mask layer, background, it can go anywhere from 2 to over a 100 layers depending how complex your scene is. If you start throwing in motion blurs, render time goes up like crazy.
Our "old" render farm was made up of 960 Pentium III-933MHz workstations(hey, they were the fastest at the time). Took up a whole floor, had its own cooling system and we had to hire helicopters to bring in steel beams to support the floor(we were up in a 31 floor high building). Felt like computer powered gods.