cam not workin

i have had a macbook pro for over a year. my cam on it used to work and i went to try it recently but it doesnt work.... it says there is no video source. any help wud b appreciated.
i only ever used it with yahoo messenger and some of the standard software applications.
any help would b appreciated,
many thanks,
conor

Try iChat, or Periscope you'll find it hear

http://www.versiontracker.com/dyn/moreinfo/macosx/32348