Some regional operators now offer competing services, but it will depend on where you are living. An installation process will typically take 4-5 days, but there are stories of it taking a lot longer - chase the company if they don't deliver.
Telefónica charges around €77,53 (end of 2004) for basic phone line installation, but this can be less if there's a competing regional operator in your area. Telefónica's standard installation package usually include an actual telephone in the price; this not free as it belongs to the company and you will be billed a monthly rental fee. We recommend you skip this and buy your own phone to save cash, but make sure you don't get charged for the rental anyway (we have heard stories of this happening). Monthly phone line rental is around €10-12.