If you have FFMPEG installed on your computer...
Here is a quick Windows guide (VFW capture method) :
http://ffmpeg.gusari.org/viewtopic.php?f=25&t=13
If you get a list (first code) with device availble and then it also makes an MP4 test file (second code) then you are ready.
However they recommend using DShow instead of VFW:
see: https://trac.ffmpeg.org/wiki/DirectShow
If you run ffmpeg -list_devices true -f dshow -i dummy
in the command prompt you will get a list of devices. One those listed should say "something camera". example output looks like:
[dshow @ 03ACF580] "Integrated Camera"
Test that "Integrated Camera" with this command:
ffmpeg -f dshow -i video="Integrated Camera" out.mp4
Use a command like this below to send to RTMP server (you must be logged in there too)
ffmpeg -f dshow -i video="Integrated Camera" -acodec aac -ac 2 -strict experimental -ab
160k -vcodec libx264 -preset slow -profile:v baseline -level 30
-maxrate 10000000 -bufsize 10000000 -b 1000k -f flv rtmp://yourRTMPServer/Type/yourStreamName
replace Type in the link with your stream type (eg: live or VOD or Play or whatever your full RTMP link is written. You did not say so I can only guess its one of these three types).