How to find out devices associated as iMessage client with my apple ID Is it possible to find out what devices have been registered to receive iMessage with my Apple ID? 

I can only see my phone number and Apple ID in iMessage settings, but not what devices are registered.
Itunes > Itunes Store > Click on email id after logging in (i.e. view account) > Manage Devices 


That should get you a list of devices, that you have your appleid enabled on. You can check those device settings to see if iMessage is enabled and if yes, under what ID.