hi,
I guess this is a bit of an old thread now, but I've got quite a few iPhone tricks, there are a few that aren't great at all, but two I recommend are firstly, Richard Wiseman's "Telepath" - this is a great effect, and well worth the money, you need to develop a good 'patter' and it requires a little bit of memory, but once you get it you will amaze people. I've done this trick many times, and only once did someone 'get' what was happening.
The second I recommend is "Marty's Magic Coin" - it requires you to know basic coin sleight, but it's fun, and fast to do - and can be very realistic. The thing I like is that there is a good variety of coins you can use, including American half dollar, which is very nice for palming work. You can also use many other nations currencies - most recently I did this with a 1 Euro coin.
The effect is quite convincing, and recently sound was added to make it seem even more realistic.
One of the worst unfortunately is the David Blaine "Street Magic" trick, I've had it freeze my phone dead twice while trying to perform it, plus the fact that it requires the audience to pay too much attention for the force to work, so often it doesn't come out well - and because it's on the phone, there's no easy way to get out clean.
Len