Samsung Android 2.3 - Manual (Page 214)

Email 214
AUG-2.3-103 Android User’s Guide
Working with message in batches
You can delete, star, or mark unread a batch of messages at once.
1 In the Inbox or mailbox, check the messages that you want to work with as a batch.
When you check one or more messages, the Mark unread, Add star, and
Delete buttons appear at the bottom of the screen.
2 Touch
Mark unread, Add star, or Delete.
You can also press Menu and touch Deselect all.
Your action affects the entire batch of messages.