You can long press any homescreen, add a shortcut to "activity" car home.
and... from xda:
Car home contains two components, the activity (this is the app we're updating) and the launcher. The activity contains the guts of the program, but the Launcher allows it to show up in the app drawer.
If you're using CM6, you have CarHomeLauncher.apk already in system/app and just need to install the com.google.android.carhome-1.apk file. If you are not using CM6, then you may need to install both the Launcher and the carhome apk if the carhome app doesn't show up in the app drawer.
adb remount
adb shell
mv /system/app/CarHomeGoogle.apk CarHomeGoogle.apk.bak
install attached apks. Let me know if there's issues.
As an aside, both LauncherPro and ADW have the capabilities to create shortcuts for activities, bypassing the need of the Launcher, but it still will not show up in the drawer.