from the post on arstechnica:
"HDMI on the PS3 only supports 480p, 720p, 1080i, and 1080p. There's no 480i support. No HDCP, no display - at all."
quote from http://www.reference.com/browse/Dell_monitors
"1503fp 1024x768 dvi, hd15."
a little google goes a long way. i'd suggest reading the first few results that pop up.