Retinasizer is a tweak that forces OpenGL games to be rendered at the native 960x640 resolution of the iPhone/iPod Touch 4.

Supported games:
- Sonic 4 (SEGA)
- PES 2010 (Konami)
- Zombie Infection (Gameloft)
- ACE Combat (Namco)
- Tiger Woods Golf (EA)
- Sim City Deluxe (EA)
- Street Fighter 4 (Capcom)
- Touch Pets: Cats (ngmoco)
- F.A.S.T. (SGN)
More games will be added as soon as the dev will tweak and test some
more.

Future plans: a settings page for adding/removing games.

NOTE: This tweak will not add any icons to your
homescreen. There are no options to configure. Use it with any of the
games listed above.

You can download Retinasizer for free from Cydia via BigBoss repo

i have not tested it but judging by these photos, it does its job
SONIC 4:


PES 2010