Available at the right price- free! I'll have to give it a look.

Since it was free, I downloaded the iPhone version. It has categories: Restaurants, Hotels, Hostels, Self-catering, B&Bs, pubs, entertainment and activities (golf, fishing, walking, tours). You can filter it by county. Northern Ireland is included. Most of it appears to be commercial content but there were (for example) directions for a coast line tour of Antrim, both driving and by public transportation.

A downside is that you have to be connected to the internet to access the content.