Some find the keyboard clicking annoying, but I find it useful in giving you confirmation that you have indeed pressed a key. You can turn it off permenantly by going to Settings>Sounds>Keyboards Clicks off. But if you just need to turn it off temporarily, like those moments that you don't want your significant other to know you're texting your bookie in church, just turn the ringer switch at the top of the left side of your iPhone off. This silences the clicks too.
