mark8par:If i connect a ps3 through my Denon 4308 amp with HDMI can i get full hd surround sound from blu ray movies or what is the best way to get the most out of it
Yes, you can certainly get HD sound from this combination - just make sure to set the PS3 to output Linear PCM audio via HDMI, then it'll decode Dolby TrueHD and DTS-HD Master Audio onboard and send to your Denon.
Keep in mind, however, that doing this doesn't utilise the decoder inside the Denon, and so it won't display DTHD or DTS-HD MA on its front panel.
If I'm honest though, with an amp worth £2,000, I'd consider investing in a more upmarket Blu-ray player that can bitstream HD audio codecs to the Denon via HDMI, so that its (most probably) superior decoding capabilities are put to good use. It's bound to sound better again!
Hope this makes sense to you!