The iPad versions of GarageBand and iMovie have been updated today. GarageBand for iPad has been updated to version 1.0.1 and contains the following new features and fixes:
Support for audio output over AirPlay, Bluetooth devices and HDMI with the Apple Digital AV Adapter
Import of AIFF, WAV, CAF audio files and Apple Loops (16 bit, 44.1 kHz)
Allows copy and paste of audio from supported apps into GarageBand
Addresses occurrences of GarageBand freezing while playing Smart Instruments
Improves overall stability and addresses a number of minor issues
A support document