Recently I had to work with some IP cameras and surveillance systems, and I played around with software and hardware making some tests here at the company before doing the real stuff.
I first got some documentation about the cameras I had here available, some old Intellinet IP cameras 550550 and 550710. They have no mjpeg streaming, and images are accesible using a java or activex plugin. Luckily there's the possibility to use javascript to retreive the images and have a live image from the camera.
The second step was reviewing some camera manager software. There are many on the web, and I spent some time reading specs, reviews and testing trials. The finalists were Go1984 and ZoneMinder. They both did the job, but Go1984 was far more easy to setup (even if the interface is not so intuitive in setting up events, schedules and motion detection) and is compatible with a large range of IP cameras.
It costs about 400 Euro (for Enterprise version), and I can tell you it's worth the money.