If you can't see it in the showroom, here's how to get Snakes Subsonic to appear:
1. Launch the phone's web browser
2. Select Options
3. Select Clear Private Data
4. Select Clear Cache
5. Go back to the N-Gage app, go to the Showroom, click on "Available Games"
6. Scroll right to the bottom of the list, Snakes Subsonic should be there
Phew! Nokia, any chance of adding an "update now" option to the Available Games page too?
Incidentally, you can see some screenshots and a trailer of the game on All About N-Gage's Snakes Subsonic page.