I got this from Droid Life. You can use it without the car dock by doing this:
1. Using AppBrains Fast Web Installer, send the app to install from this page.
2. Once installed, head to home screen with space on it.
3. Hit Menu>Add>Shortcuts>Activities (you need LauncherPro installed).
4. In Activities, scroll down to Car Home and tap on it.
5. Now select Car Home com.google.android.carhome.CarHome.
6. You will now have a shortcut to the app on your homescreen.
I downloaded it onto my computer and dragged it onto my X. At first I couldn't tell it had transferred but once I plugged it into my car dock, both this and the standard mode popped up and I was able to choose which one to default to. After spending a couple of minutes with it I like it a lot especially since it is extremely customizable. I can add whatever apps I like, wherever I want them. Very Google which is Very Nice!
I've got a long drive today so I'll post more after I truly get a chance to play with it.