i think it is but i think it would be best to also submit your business to the online yellow pages and if there a website where people can go to find businesses in your local area it'd be good to submit there too.
there is also google local, yahoo local...etc
this way you will be reaching people no matter where they are looking, alot of people still use phonebooks but there also seems to be a transition going to where the thing to do is 'google it'.
for me when i need to find something i look to google...i have google as the homepage for my phones browser so if im driving and need to know where that hareware store, pet store, coffee shop is i google it.
ah well im rambling hope that helped