Criminal Law Questions? Ask a Criminal Lawyer.
It is illegal for a property owner to have a camera pointed directly at your house 24 hours per day. This would be an invasion of privacy or more likely- harassment. That said, a land owner is allowed to have a camera set up for surveillance of his property, and if it happens to catch your house... that would not be illegal.
It really does depend on the specific circumstances of your case. The real question is why they are doing it and if the actions amount to harassment.