I once set up a Belkin Netcam at a vacant house that was for sale and had already seen a break-in. I borrowed a MiFi device from someone, added it to my cellular account, plugged it in in the house, which gave me a cellular-based Wifi basically. Then I just set up the Belkin using that Wifi and would get emailed pictures when motion was detected. I could also go in through the app and view the camera with audio live feed.
http://www.belkin.com/us/p/P-F7D7601/
It was a nice setup and gave everyone peace of mind. Only thing was sometimes the audio on the live feed had strange sounds. I think maybe it was picking up kids playing out in the street or something, and possibly also picked up and distorted sounds from the hot water heat in the house. Once I checked the live feed from work after I had an email with pics and I was hearing a banging noise for quite some time. I watched for quite a while, eventually called the police, explained the situation that there was previously a break-in and I was hearing something unusual. Just asked if someone was available if they could drive by and check it out. Ended up actually being an officer I know well who went, there was nothing there.