I would recommend a dedicated DVR for this, rather than using a PC, they are now available with internet/phone connectivity options. Most have motion detection software which can be used to activate/alarm the system.
With regards camera�s, most that are claimed to have night vision use some form of infrared illumination � but are normally very limited in range due to the power required to light a large area.
I have a home security cctv system using B&W cameras which are speced down to 0.003 Lux, which I reckon is around the sensitivity of the human eye. Although not of brilliant quality, the camera�s give acceptable image results under street light levels (avoiding the need for dedicated lighting).