Neogaf has confirmed that the custscenes of the x360 version of FF13 run at 576p . It was confirmed before that the ingame FF13 x360 version ran at 576p days ago.beyond3d has also confirmed the FMV resolution of x360 version to be at 576p.The cutscenes of the ps3 version runs at 1080p,as confirmed by eurogamer's digital foundry division
edit:
The full set of 576p scans with analysis can be found here:
http://www.sendspace.com/file/h8kyb8
One analysis chart is here :
http://www.neogaf.com/forum/showpost.php?p=20074288&postcount=3826
edit2:
the scans are proven to 576p by beyond3d tech gurus too. The guy got banned for using provocative words . See other images of x360 versions as well
Update
EDIT:
The user jurai got banned because of using the pirated version of x360 ff13.the analysis of 576p resolution for fmvs has been acknowledged by tech gurus of beyond3d as well
BEYOND3D Has confirmed that the ingame FMVs of x360 version runs at 576p too. This comes after a confirmation that ingame ff13 runs at 576p on X360 too
http://forum.beyond3d.com/showpost.php?p=1401775&postcount=1485
"Still 576p 2xMSAA "
The FMVs on the ps3 version runs at 1080p. the ingame ff13 on ps3 runs at full 720p native