Root Checker Application
If you want to check if you have root (superuser) access on your Android device, try out XDA forum member joeykrim‘s Root Checker application.
The app provides Android users with a simple method to check for root access on their phones, and will also provide a simple notification as to whether or not Busybox has been installed properly. There are two simple buttons in the app, clearly marked with their functions. All you have to do is click one or the other depending on what you want to check.
Please note that this application does NOT provide root access.
Root Checker is available to download free in the Market. For more information, head on over to the application thread.