Do not sign up to Yell, a serious waste of money, I learnt the hard way.
To get the ball rolling (free options) try the following:
- Register your business on Google Maps/Places (get yourself verified) and ask customers you have worked for to leave some reviews.
-Sign up a Facebook Business Page do the same as above. FB will try and get you spend money to "boost" your visibility, don't.
- Setup a basic 1 page website (only bit where it will cost a bit of money)
- Search for free business listing sites FreeIndex etc post your business details there.
Hope this helps bud.
A