It's limited to specific locations, and only available with a data connection.  See [this question on the location limitations][1] and [this question on alternatives][2].


  [1]: https://android.stackexchange.com/questions/1854/does-android-come-with-free-navigation-in-non-us-contries
  [2]: https://android.stackexchange.com/questions/227/what-replacements-are-available-for-google-maps