Dear santhanar,
You can find plenty of example programs in Example Finder. To access Example Finder from your LabVIEW development environment, open a blank VI, then click on Help»Find Examples. Once you have Example Finder open, the you can select the Browse tab. The sound example programs are located in Hardware Input and Output»Sound. I recommend starting with Sound Input to File VI and Sound Player VI. In Sound Input to File VI the input control Device ID refers to your default microphone input. You can plug in a microphone and record sound directly to a WAV file. There is no direct mp3 support in LabVIEW at the moment. However, you can play mp3 files by using ActiveX controls. Please refer to the discussion forum titled Can LabVIEW play mp3 files continuously? and also this NI LabVIEW MP3 player example.
Search our website for WAV and you will find more examples. In the future could you please include the version of LabVIEW you are using?
Hope this helps!
Kalin T.
