Apple iPhone OS 3.1 - Manual (Page 127)

Listen through the built-in speaker: Tap Speaker.
Managing Voice Memos
Delete a voice memo: Tap a memo in the list, then tap Delete.
See more information: Tap next to the memo. The Info screen displays information
about the length, recording time and date, and provides additional editing and
sharing functions.
Add a label to a memo: On the Info screen tap , then select a label in the list on the
Label screen. To create a custom label, choose Custom at the bottom of the list, then
type a name for the label.
127 Chapter 15 Voice Memos