There are 2 main English Guides to the region; that published by RockFax and that written by Chris Craggs.
The other option is to buy some of the local Spanish Guides. There are a number of these that tend to cover very specific areas of the Costa Blanca, Sella, Penon, Ponoch, etc. Most can be purchased at the sport shop, Sport O'95, in Calpe. See The Shopping for details of how to find this shop. Or you can try buying them online from the Desnivel library section.
Costa Blanca Rock
There is an exciting website that details new developments on the Costa Blanca. Called Cost Blanca Rock this site gives topos to some of the latest crags being developed. The topos are of surprisingly high quality and use the widely recognised RockFax symbols to denote features.
The site details several new crags in several areas including some new work around Calpe. I also happen to know that more is on the way so it might be worth checking this website on a regular basis.
The website for the Compass West school of international climbing now carries a number of topos for their latest developments. The Edwards family, that run Compass West, have been power houses for development in the Costa Blanca for many years and almost single handedly developed the fantastic Echo Valley. The topos on their website cover further new developments in Echo Valley as well as a huge mountain route at Bolulla in the Guadalest valley.
This Spanish site holds topos to many areas of Spain including some on the Costa Blanca. Simply select Croquis from the side menu and then select the Alicante region on the map.
Desnivel is the national climbing magazine to Spain and runs a crag finder on its website. Mostly these entries just contain some background information but one or two also contain topos. There is even an English version.