We're getting started with Infrastructure Modeler here in support - here are few things that I've found useful, and you might enjoy:
Great video of what can be done: http://www.youtube.com/watch?v=UGXtgW6yQyM&feature=related As I understand it, this customer produced the video 3 days after first downloading the software.
Video tutorial: http://www.youtube.com/watch?v=LEV7qstN__8
The product family blog has lots of good information: http://atlandsend.typepad.com
More coming soon, but let us know if you've tried it out, and if there's anything you'd particularly like to learn more about!
Here's a screenshot of a sample model I'm working on. Bonus points if you can identify where it is. With any luck, it'll have some imported building models in the next post.