I did the above and connected a Microsoft 720p HD camera.
I changed the stream to 1280x720 and auto-started the mjpg stream.

Just edit /etc/rc.local and paste this:

cat rc.local
echo before-mjpg
/usr/bin/mjpg_streamer -i "/usr/lib/input_uvc.so -f 30 -r 1280x720 -d /dev/video0" -o "./output_http.so -w ./www -p 8080" -b

echo after-mjpg
exit 0

Then reboot and then you have it!