I think "no" is the short answer.
What the keynote was referring to was that all the devices with the same identifier ring at the same time. So if you have, say, a Mac and an iPad 2 both signed in with the same Apple ID, they'd both ring. Unfortunately, you don't sign into Facetime on your iPhone 4 with an Apple ID...
At the moment:
You are able to log into all Apple devices with an Apple ID for use with both Facetime and iMessage. For instance I can log into an iPhone, iPad, iPod Touch, and a Mac all with one Apple ID. If someone Facetime calls the Apple ID, all devices will ring simaltaniously. If however you call my phone number with Facetime, only my iPhone will ring with a Facetime call. The same goes for iMessage. I can send and receive a message on all my devices through my Apple ID, which will sync that message accross all devices. However if I send or receive an iMessage usuing my phone number, it will only appear on my iPhone.
With iOS 6:
You will have the option to unify your Apple ID and your phone number. This means that all the functionality of the above still exists, however you will now be able to send and recieve iMessages and Facetime calls on all devices using your phone number or your Apple ID as they will both be unified.