MacBook Pro Retina
You will know how to adjust the resolution of your Mac Retina Display and how to set up an external display.
How to adjust the screen resolution of my MacBook Pro Retina display ?
Your MacBook Pro with Retina display has a resolution of 2880 x 1800 pixels and starts with the default mode that is recommended to use your Mac.
If you want to adjust the display resolution, select "Preferences" from the Apple menu. The Retinan display offer an adjusted resolution to display text and larger objects on the screen or display them finer (smaller in fact) and to have more space on screen.
Note: the "scaled" resolution does not offer the same visual quality than the native "Retina". The scaled resolutions may have impacts on graphics performance depending on the application you use.
What applications supports the Retina Display mode ?
All applications included in Apple Mac OS X Lion on your MacBook Pro with Retina display support the "Retina Display" mode. These applications include: Mail, Safari, iCal, Address Book, iChat, FaceTime, Photo Booth, and TextEdit. But also iPhoto, iMovie, iTunes, Aperture, Final Cut Pro X, and finally Motion, all of them support the "Retina display"
To read the full FAQ published by Apple, go straight to Apple Support web site.