It is true than on some systems the iCamSource (as well as any other webcam application) does take control of the webcam, making it so that no other application can do so, but it doesn't seem to be a consistent problem. For example, I can connect more than one iCamSource, Photo Booth, and iChat to the same webcam on my Mac without issue, but once Skype is brought into the mix, it won't connect to the camera until all of the other applications are closed. Also, if you start Skype first, no other application can access the webcam until Skype lets go.
If the iCamSource did not keep connected to the camera then a large portion of iCam's functionality would not be possible: Motion Events could not be recorded, Push Notifications could not be sent, and if some other application had greedily taken control of the webcam and not released it, you wouldn't even be able to connect to your camera. Even if another webcam application had released the webcam, but perhaps left it in an odd state where the solution would be to unplug and re-plug in the webcam (something that has definitely happened to me before) then if you're away from your computer there's not much that can be done.
Since iCam is largely a remote monitoring app, whenever things go wrong with the computer running the iCamSource, there's not much you can do.
We recommend that if you are physically at your computer and want to use Skype or some other webcam application, just Stop the iCamSource, use your application, and re-Start it when finished.
To add to what OUAnthony said about the iCamSource not running at boot and running it as a service, that is correct, but you can also copy the iCamSource shortcut into the Startup folder in your Start Menu so that it will launch when you login. Clicking the Auto Start checkbox will cause the iCamSource to "Start" as soon as it is launched.