David bought an Epson Powerlite 2030 projector, but the image isn't very good with DVDs. Leo says that DVDs are 480p, and get upscaled to 1080p. If it's not very good quality, then the projector isn't upscaling as well as it should be. David should use HDMI cables from the PS3 to the projector.
He should be mindful that if the cable he uses isn't HDCP compliant, the quality will go down to 480i, and that could be the culprit. He should also try using the PS3 to upscale. He should look at the settings, and tell both the PS3 and the projector to provide the highest quality it can get. They can upscale to 1080i.