That's sadly not a problem with Ubuntu, it's the typical vendor lockdown on drivers and specs. It's indeed relatively bad for webcams , but there are at least open source drivers for logitech and philips webcams (even though they do not work as well as with the proprietary drivers)
Check http://www.linuxplanet.com/linuxplanet/tutorials/6463/1/ for more informations (or google "linux webcam")