It is very basic but there are VideoChat examples that you can use as a starting place. There is Flash Pro (.fla) and Flash Builder (flex) examples
/examples/VideoChat/client
/examples/VideoChat/clientFlex
There is an unofficial example that was made in Flex 3 and includes a little more in the way of logging in and user presence here
These examples are staring places, there is a not a tutorial or guide to further development. These are Flash client examples.
Richard