Hi,
CatAir will be a low cost carrier owned by Iberia and 4 more companies (each with 20% of the shares) that will be based in BCN. Iberia's willing is to cancel most of their routes (probably all except the air shuttle with Madrid) from BCN and let CatAir fly them. They will start with 4 or 5 A320s (probably leased from Iberia) and they will increase their fleet to about 30 A320s during the first year. They also want to be in the stock market in 2 or 3 years. Operations are scheduled to start in October. It's also been said that they will be codesharing with Iberia some of their destinations. Their brand/commercial name will be "clickair.com" (altough this is not yet confirmed and some others brands such "airmediterranea" or "airmediterraneo" are beign discussed).
The routes cancelled will not affect Iberia's regional operator "Air Nostrum", at least in the first stages. In the beginning of all this are Iberia's plans to operate ONLY to/from their Madrid hub.
Anyway, there is nothing official yet and they haven't confirmed any route.