I have a Samsung HP-T5054 plasma 720P(it is set on 1080i at the moment). The main problem I have is watching blu ray movies. In the main menu of the PS3 the black levels are great but when I play a blu ray it isn't. When the blu ray movie is being loaded you can see grain on the black which is very annoying. The ps3 is hooked up on HDMI. It only looks ugly in a blu ray movie. Is this a calibration issue?

^Have you tried messing with the settings? Changing it to 720 instead of using 1080i?

I have a Samsung HP-T5054 plasma 720P(it is set on 1080i at the moment). The main problem I have is watching blu ray movies. In the main menu of the PS3 the black levels are great but when I play a blu ray it isn't. When the blu ray movie is being loaded you can see grain on the black which is very annoying. The ps3 is hooked up on HDMI. It only looks ugly in a blu ray movie. Is this a calibration issue?

It sounds like a calibration issue, or it could be that the loading screen isn't pure black. Calibrate using DVE or Avia. if the loading screen still isn't black, don't worry about it.