Workflow to make windows on building I'm new.. I'll start with that...  I'm building a house for uploading to SecondLife. Well, trying anyway.  I built my walls of one piece, using loops to create spaces for doors and windows.  I've mapped and textured, and created glass for the windows.  So my question is about the window frames.  Is it better to just lay a window frame over the existing glass in the wall, remove the face from the wall that are the window and make a frame with glass and set it in, or should I just create the frame out of the wall?  or does it even matter how you do it?
I would recommend to cut holes in the walls using Archimesh and placing the glass frame inside the window frame. Reasoning behind it is that you might want to play with sliding windows etc. But at the end the goal of your project decides mostly what approach will work best.

You can use Archimesh for house/room modelling. But will only work if you started from scratch. In other cases you need to cut the holes your self by for example the knife tool or re-organizing your topology.

Using Archimesh

The Archimesh Add-on is a fine add-on what can make a room, place windows and doors in the location you like and hit a button called Auto-Holes that will cut the holes for you. 

The Archimesh add-on is distributed with Blender by default, but it is disabled. You just need to enable it in the User preferences.