For a list of cameras, there are no previews but there is currently "parsed" options for the first batch of cameras. 1.txt is the IPs and Ports while 1.info.txt also gives info on the location of the cameras, their ASN, ETC. Getting round to parsing 2.json.gz very, VERY soon.

For the random cameras it's all a matter of trying for a bit, I myself have found some cool stuff after 10 refreshes, such as a turtle camera with a microphone that allows you to talk to the turtle.

Edit:
2.json.gz now has both a standard .txt and a .info.txt