You probably know, that NAVAIDs (VORs etc.) transmit their IDs using Morse code.
You can listen to it turning NAV1 or NAV2 audio on, identify the tuned NAVAID
and verify that transmission of the right one is being received (which sometimes may be a live-or-die issue).
AFAIK, NAVAID verification using Morse (audio) is recommended even in the case of the most modern flight management systems and computers.
I've found a nice piece of Morse learning software here (Vista compatible).
Further reading about Morse code available here (Wikipedia).
Enjoy
MW