Another offering from www.themacbox.co.uk, Cinema Times is a neat custom webpage for finding film showing times near you. It'll help you locate your desired cinema and also provides quick shortcuts to information on the film you want to see, including trailers and reviews. It's only a shame it doesn't provide contact information or shortcuts to booking services, though it does let you mail showing times to friends. Despite a couple omissions, though, it's still a great little tool.
One of the first and still one of the best iPhone apps, the Last.fm application takes an already excellent web service and delivers it to your iPhone and/or iPod Touch. It's a well designed and fully functional one, too, giving you access to Last.fm's excellent internet radio service and music recommendation system, while also keeping you informed of events involving your favourite bands. Streaming music even works over 3G, though you'll need to keep your charger nearby if you want to use the service extensively.
Yet another effort from www.themacbox.co.uk, if you need to look up a phone number or address then the BT Phonebook is what you need. Numbers can be called just by touching them and addresses will take you to Google Maps. Why pay money for the extortionate phone directories, when you have all you need on your iPhone?
It's still not the finished article, and in some respects is inferior to the web version, but the Facebook app is still a must for anyone who uses Facebook even semi-regularly. It does all the basics well enough, makes browsing photos particularly easy and informs you of new messages. It's just a shame profiles and other features aren't so fully implemented. Hopefully this will change with time.
Here I Am
Only compatible with the iPhone 3G, Here I Am is a very very simple application. It uses the GPS to send an e-mail with a Google Maps link, enabling you to quickly tell people where you are and use Google Maps to work how to get to you. A great and practical use for the iPhone 3G's GPS chip.
That concludes my list of my favourites. It doesn't include a lot of popular applications, including Apple's own Remote app or the recently released Simplify Media network streaming application (I haven't had the time to try that just yet), but hopefully it contains some you will find useful.
Feel free to share other undiscovered gems, including paid for apps, in the comments.