I have one asus router can do it,and there're plenty of them in other brands.
Also,there're some wifi webcams.
The beauty of router or standalone webcam is that you don't need to leave your pc run all the time.
you can use regedit(if you know what to find) or msconfig to to stop it from loading in the first place.
Once you shoot up msconfig,you'll be amazed at how many programs has been running background out of your knowledge