Use our collection of over 140,000 page scans (and growing) as an enormous hymnal. Put your iPad or other tablet device on your music stand or piano, enter in a hymn title or use our melodic search engine, and music for just about any hymn you can think of is instantly available.
The average person in the pew will continue to use printed hymnals, or song sheets inserted into the order of service, or projected lyrics on the big screen behind the preacher. But this iPad app is going to be a major boon for worship leaders and musicians. Have a request for a specific hymn for a memorial service from the Army and Navy hymnal (as I did once)? — there it is on your iPad. Need to find the more traditional words for a Christmas carol? — just use the search function.
One final thought — I really hope the next Unitarian Universalist hymnal is also sold as an iPad app. I doubt many people will use it in Sunday services, but there are a fair number of people who keep a hymnal at home, and the iPad app would potentially be a lot cheaper, and easier to use.