Signal 1.0.2 was released last week, this version includes full support for the iPod Touch, an updated view for the playlist, a software update notification interface for Windows, and several stability and performance fixes. Full details are available in the releases notes.
In particular, the iPhone version is now much better at handling situations where the iPhone initially wakes up on EDGE and transitions to Wi-Fi. Signal will now automatically detect that it does not have a connection and queue up commands to be sent as soon as the iPhone re-joins the Wi-Fi network. This means you can wake up the iPhone and tap pause/play, next track, etc without having to worry about whether or not the iPhone is on the cellular data network - Signal will take care of getting that command sent as soon as there is a connection.