DJs who didn't take so Samsung's Beat DJ phone have now got another option - to pick up an iPhone and grab Quixonic's "Quixpin" application.
It's an iPhone app that lets you cue, beatmatch and mix between two different tracks on one handset. Simply cue up the songs, then use the touchscreen to tweak the speed, EQ and crossfader. Simple and full-featured, though there currently isn't a way to tweak the speed without also adjusting the pitch - a feature common to most DJ-standard CD players.
There's no way of listening to a mix before it goes out, either, meaning that you have to rely on the graphic display and your ears being faster than whoever you're DJing to, to work out whether or not your beats are matched sufficiently.
Quixpin costs £4, and requires the 2.0 software update to use. It's available now.
Update: According to the video, the left channel of the output is a cue channel, whereas the right is the master out. On the one hand, that means that you can listen to mixes before they go out. On the other, it means that the master out is in mono, and it'll be a pain to use without an audio splitter of some sort. Let's hope that's an option that's easy to turn on or off.