This rumour was started when someone was poking around the SDK and found images in the Twitter.framework that have a retina-like resolution of 1536×2048. This is far from a confirmation, but we have seen that resolution tossed around before.
Apple may be secretive about a retina display, but its rival and supplier Samsung is embracing the technology. The Korean company recently introduced a retina display for tablets with a 2560×1600 resolution and it looks fantastic. [Techunwrapped via MacRumors]