A new 34 set of 33 street names and 1 post, all can be found under Decor/Misc Decor and all cost 0.
Use the cheat "moveobjects on" to place the street name on the post. The street names and the post have a 2 block offset in the X - axis so they can be placed on pavements. The street names can also be placed on the post of the "direction signs". I've used the "World Editor" button to create a few 10 x 10 lots and to place some street names on open ground.