Peter wants to get some internet enabled security cameras. Leo likes the Nest (formerly DropCam). Leo recommends checking out the Wirecutter. They have a great roundup of internet enabled security cameras. They like the Nest Cam and the NetGear Arlo. Axis makes excellent professional grade IP cameras.
One of the advantages of Nest is that it records in the cloud and you can go back into time to see what happened on any given date. You have to pay for it, but it's a great feature.