There are few ways to connect HDMI cable to LCD TV.

First:-
If you have LCD TV only without home theater system. Directly connect PS3 to LCD TV via HDMI cable. The HDMI cable carry both audio and video to LCD TV and TV output picture and sound.

Second:-
If you have home theater system without HDMI port (but with optical port). You can connect through this way:
For video, PS3--->HDMI cable--->LCD TV
For audio, PS3--->optical cable--->home theater system
Note: you need adjust PS3 sound setting to optical.

Third:-
If you have home theater system with HDMI port (but not HDMI pass through). You can connect through this way:
For video and audio, PS3--->HDMI cable--->Home theater system--->HDMI cable--->LCD TV
Note: you need two set of HDMI cable for this connection.