Architectural Lighting

[Philthy]

Hi,
I was wondering if anyone who works with producing renders for Architecture here is able to give me a few tips on how to produce good lighting etc.

I have rad the tutorial on the asgvis.com and was wondering what is an environment map (how does it work, and where I can get them from, etc.)
And just general tips so that I have a starting point to muck around with.

Thanks