Connect Flash & Unity through an socket connection

It is possible and it does work, still awaiting user feedback but and embryonic demo can be found at the link below, what you must do is respond when flash asks for a policy file through the port it opens, reply with the policy and away you go, hope this helps.

flash unity cam at fusedworks.com

I'm looking into this possibility too and found some worrying details about sockets in the actionscript livedocs.

Especially the second restriction sounds like it could prevent a flash control and a unity control in the same webpage to communicate with eachother (as you're aiming the socket at localhost). Can anybody confirm/deny this ?

When you use this class, consider the following security model:

• Sending or receiving data is not allowed if the calling file is in the local-with-file-system sandbox and the target resource is from a network sandbox.
• Sending or receiving data is also not allowed if the calling file is from a network sandbox and the target resource is local.
• The calling file and the network resource being accessed must be in exactly the same domain. For example, a file at www.adobe.com can send or receive data only from sources that are also at www.adobe.com.
• Websites can permit cross-domain access to a resource through a cross-domain policy file.

I found an interesting case where a developers used a webcam directly from unity (I don't find flash stuffs in it). But in documentation no a word about the webcameras at all. How it even possible?

From docs:

Unity has extensive support for C, C++ or Objective-C based Plugins. Plugins will work in standalones only. They are disabled when building a Web Player for security reasons.