Using ModelSim-Altera with Altera designs

I just found it, so I'll bookmark it and read it later. Right now, I'm trying to setup a ModelSim simulation environment for the PC. The first reply to this thread example gives me a good starting point.

I do have a couple of questions......is it really necessary to always for each simulation performed? And if the Altera libraries are already come pre-compiled, how do you "point" to them? Is there a ModelSim setup file that is read by vsim? Or would I need to use vmap and vlib?