Question on masking a person (jpeg or any other format)

hey people!

     This came up pretty puzzling to me , i see a lot of sites that have pictures of people but there background are not shown. Now i want to do this for a site i am building. Do i have to manually trace the picture that i want to use in flash or is there another of me doing this?

Btw the file is attached. If anyone would kindly show how to do it
plese help :stuck_out_tongue: