iPhone Recording Application
Griffin Technology has released a free iPod/iPhone app called iTalk that let's you use the microphone of the iPhone to make recordings:
iTalk Recorder lets you record, pause, resume and append to existing recordings, manage the list of your recordings, and add text notes, all on the touchscreen of your iPhone or iPod.
You can then sync the recordings to your Mac or PC using the (also free) iTalk Sync application:
iTalk Sync is a dedicated app you run on your Mac or PC that searches your Wi-Fi connection to find any iPhone or iPod touch that's running iTalk. It lets you drag recordings from your iPhone or iPod to your computer's desktop.
iTalk seems like a great way to capture quick song ideas or record brief interviews with other guitarists.
(via Daring Fireball)