You can get any amount of Meditation Apps for the iPhone. There are, for example various programs which play soothing music or some other sound for you to relax by. Others give you a step by step guided meditation using somebody's patented technique or other. I won't bother with those here as I've never actually downloaded any of them neither can I imagine myself doing so. I have tried a few timers though.
A timer is a useful meditation accessory. A clock on the wall is OK, but you really do need something with an auditory alarm if you are going to minimise the temptation to go looking at the thing all the time. If you are in a monastary a bell in a tower or a monk with a large gong and a hammer will do the trick nicely, but for those of us in more suburban environments, we just have to make do. The sort of little countdown timer you can buy from any electronic store will work fine, as will the stopwatch function of your watch. I have an iPhone, and its built in timer, works simply and well, and as my phone is nearly always in my pocket, it seems a good choice for me. There are a number of purpose built meditation timer apps as well , of course: as there are apps for just about everything else you can think of.
The simplest are ones like Mind, a free app which has a simple user interface, and is essentially just a timer which can be set for a period of from 1-60 minutes and rings a bell when the time is up. There are a lot of similar products in the App store, most of which cost $US.99 but I can't quite see why you would bother with one of these instead of the inbuilt iPhone timer.
Other meditation timers offer other features of varying degrees of usefulness. Most will give you a choice of alarm sound, and allow you to set a bell to ring at various intermittent points in your alotted meditation time: say, every ten minutes, for example. Some will allow you to set a "settling down" period before your meditation or a "recovery" period after. Many will keep a record of your meditation periods and some will provide statistics on your progress. Some will allow you to keep a journal, and make notes on your meditation sessions. Some will only time for a preset period, and some will allow for a more open ended approach.
I find the statistics and note taking features a mixed blessing. While it is salutary and helpful to have an objective record of how my practice is going, at least in terms of time, the numbers continually invite me to treat my practice as a performance, and to judge myself with the resulting traps of guilt and pride. Similarly, a journal can open the temptation to "rate" myself on the quality of the session, which is, again, to miss the point entirely.
With that in mind, of the apps I have seen, Equanimity is no doubt the most elegant and simplest to use. The interface is clever, and easy to see in dim light. It has a thorough set of statistical information, including a graph, and allows for a journal. It does not allow for the use of presents, and when the final bell sounds the app abruptly shuts down, which I find a nuisance.
Insight Timer has a quite complex interface, though it is easy to use, once you have learned it. It allows for the user to set up a meditation session: length, interval bells, warm up and cool down period, all that stuff, and then to save that session as a preset; it allows for any number of presets. It has a satistics feature and a journal, and one other intriguing, though only marginally useful feature. Using "Insight Connect", you can see who else in the world is currently using Insight Timer, how long they are meditating for, and even a little map of whereabouts they are. Clever! But why?
Meditate has a very pretty interface, with user selectable background pictures. It is clear and simple to view, but I found it a little confusing to set up and use. It has a very basic statistics feature, accessible only through the iPhone settings menu. The statistics records only completed sessions, so if you are worried about such things, don't quit 30 seconds early!
The program I have been using mostly is iSamadhi. It has a clear, simple set up screen and is easy to use. it allows for customisable presets, but the feature which I use the most is a simple button which sets the timer going with no preset end point, but which rings a chime at regular, user selectable intervals. It has a basic statistics gathering function which allows for note taking. It allows for a choice of background pictures, including your own if you so wish.
All of these apps are cheap enough that you can purchase a couple of them, try them and see which one suits you best. Otherwise, get your best beloved to dress up in an orange robe and whack a gong.