Real Tide is an iphone app for Iphone that I have recently discovered. I have tried a bunch of different tide programs both on droid and iphone and this the best one I have ever used imho.
It’s fast, stable, easy to find your location, does current speed, sunrise sun set, and best of all the interface is super easy to use. One button finds your location and gives you the tides. Slide you finger and you see it all. Low tide,mean low tide, high tide etc. Everything is just there and easy to find. If you’re not satisfied click on the map and pick the one tide station you want.
The company that make this app is called Fly To Map. The app is priced at $1.99 but I believe it is worth it.
They also make a version for the Droid which is free. The droid version is not as robust and lack a few features but a still a nice app for free.