As others have indicated, it's strictly illegal to provide reverse directory searching facilities (whether online or on CD) within the UK.
When telephone directories first became available on CDs (before web-based directories), the 'professional' editions offered reverse searching. This was quickly challenged by people who pointed out that, for example, a young woman who meets a guy at a nightclub might be prepared to give him her phone number but not want divulge her address until she gets to know him better. The matter came before the the Data Protection Registrar (who is now called the Information Commissioner) and it was quickly decided that offering reverse search facilities breached the Data Protection Act and that anyone providing such facilities would face the strong possibility of a lengthy prison sentence.
Chris