How can I change my aspect ratio?

How can I change the aspect ratio on my webcam (Acer Crystal Eye - built in) so that when I film using the webcam from 4:3 to 16:9? I use Picasa to capture the video, so would I need to change the setting THERE or on the webcam itself? Either way, how would I go about doing that? Thanks in advance :)How can I change my aspect ratio?Your webcam isnt capable of this to begin with. Even if you did find software to do this, it would cost a small fortune and you would end up with people that looked like fat pygmies