Is retina text in a non-retina OS X Application possible?
Applications using standard Cocoa APIs should get retina text for free. 

This was the same way it was released with the iPhone 4 in iOS. If you used standard UIKit, you basically got it all for free, and just had to update resources, etc.

So, with a Retina MBP as of right now, many apps need to add @2X resources (for things like images, etc), but otherwise standard applications should render all other content as retina.