Does Google Galaxy Nexus has Visual Voicemail? I just realised that I cannot find any button or option in my Google Galaxy Nexus for Visual Voicemail, whereas iPhone and many other Android phones do have such feature.

Is there no visual voicemail in Google's Galaxy Nexus?
Usually on android phones this is a carrier supplied feature.  You can get some visual voicemail app from the play store, or you can move your voicemail from the carrier's system to Google Voice, which provides it.