pboss,
Amazon has called it an experimental feature since 2007, when they released the Kindle 1. Here's a shot of my Kindle 1, googling:
http://bit.ly/grandpa-kindle
The Kindle 3 is the first time their marketing for the Kindles with 3G actually had the following words (on the product page)
"Free 3G web browsing (experimental)"
So I think we're good for at least the next year.
Most of the time, those of us with home/office WiFi are on the WiFi anyway.
- Andrys
http://kindleworld.blogspot.com