The available command line arguments are:
-u=<login-string>
-p=<password-string>
-v=<video device index>
-a=<audio device index>
-url=<IP Camera MJPEG URL>
-cu=<IP camera login>
-cp=<IP camera password>
-desc=<iCamSource description>
Obviously, you don't need to use all of them. If you don't specify a login, it will use the login stored in the registry (ditto for most of the other variables)
An example batch file entry for an IP camera would be:
start iCamSource.exe -url=http://192.168.0.99:8202/cgi-bin/video.jpg -cu=MyLogin -cp=MyPassword
An example batch file entry for the first USB camera in the Video drop down list would be:
start iCamSource.exe -v=0 -a=0
Both of these will use the login, password, and description stored in the registry, since they aren't specified on the command line.
I hope that info helps.