Apple iPhone OS 3.1 - Manual (Page 30)

Lists
Some lists have an index along the right side, which helps you navigate quickly.
Find items in an indexed list: Tap a letter to jump to items starting with that letter.
Drag your finger along the index to scroll quickly through the list.
Index
Choose an item: Tap an item in the list.
Depending on the list, tapping an item can do different things—for example, it may
open a new list, play a song, open an email, or show someone’s contact information so
you can call that person.
Return to a previous list: Tap the back button in the upper-left corner.
Zooming In or Out
When viewing photos, webpages, email, or maps, you can zoom in and out. Pinch your
fingers together or apart. For photos and webpages, you can double-tap (tap twice
quickly) to zoom in, then double-tap again to zoom out. For maps, double-tap to zoom
in and tap once with two fingers to zoom out.
30 Chapter 2 Basics