i'm using a optical cable for my sound on both my ps3 and 360.

i notice when i click the display button on my ps3 remote it tells me that the sound is multichannel and not 5.1

is there something in the ps3 settings that i'm not seeing?

Check the audio settings in the menu and set it to bitstream for optical, that should do it.

nope still the same results friend

OK, when you press the display button on the PS3 during a movie, what EXACTLY does it say?

If it says "Linear PCM" you need to change audio tracks to the Dolby Digital or DTS option ON THE MOVIE DISC if you want surround sound via optical or else it is 2.0 stereo ONLY.

Basically, for Linear PCM, TrueHD, and DTS-HD, HDMI is the only way to go (except DTS-HD will put out DTS via optical).

This is assuming you chose "Bitstream" under the BD/DVD settings in the XMB.