This is pretty easy stuff but I suspect there are folks out there that might be interested.
Yes, there are other ways to do this...
For those who wonder "why two GPS units?", the short answer is because they both do different things well.
Yes, the glove box still opens. No, the GPS and XM radio do not interfere with the Air Bag path. Everything except the bracket comes out in about 30 seconds for hiding while away.

Click for the part numbers and brief stupid-easy install instructions
The little Crossfire is pretty easy to find in most Toys 'R Us stores for a dollar or two. Mine is a Geocaching Travel Bug. I log it into the caches that I find when driving the Crossfire.