If you take it to the vets (or dog warden) they will probably scan it for a microchip and be able to notify the owner (or if it has no microchip they can at least log its colour etc).
You could put a post card in your local shop or post office to let somebody know that they have lost their cat,someone might be missing him/her so much.
Put a poster on a lampost/tree near your home with the details. Also a card in your local supermarket, and notify any local vets as that is where owners will ring to see if one has been taken in.
maybe contact a local cat chairty incase someone has reported a lost cat - ring your local vet and ask if you can take it there to check for a chip
:-(