PS3 surround sound question

Hi guys, probably a stupid question but here goes....

I'm considering getting a PS3 and reading the technical spec I see the sound is descibed as Dolby 7.1 ch. Will that work OK with my 5.1 sound system? (I would be using an optical connection.)

Should I use DTS instead or doesn't it make any difference?

I'm new to all this as you can probably gather!

It works with my 5.1 system.

If you can use Dolby then do, either way, you can select both as an option for the PS3, its best off to have both ticked because some games dont do DD.