Mac users with OS X have most of the Windows XP core fonts installed if Internet Explorer 5 (or newer) is installed on the Mac. IE5 and newer installs the following fonts on Macs and Windows computers:

Andale Mono
Arial
Arial Black
Comic Sans MS
Courier New
Georgia
Impact
Times New Roman
Trebuchet MS
Verdana

Fonts installed with Mac OS X

If Internet Explorer 5 or newer also installed:

American Typewriter
Andale Mono
Arial
Arial Black
Arial Narrow
Arial Rounded MT
Brush Script MT
Capitals
Apple Chancery
Baskerville
Big Caslon
Charcoal
Chicago
Comic Sans MS
Copperplate
Courier
Courier New
Didot
Gadget
Georgia
Geneva
Gill Sans
Futura
HeiseiKakuGothic
HeiseiMincho
Helvetica
Helvetica Neue
Herculanum
Hiragino Kaku Gothic Pro (OpenType)
Hiragino Kaku Gothic Std (OpenType)
Hiragino Maru Gothic Pro (OpenType)
Hiragino Mincho Pro (OpenType)
Hoefler Text
Impact
Lucida Grande
Marker Felt
Monaco
New York
Optima
Osaka
Palatino
Papyrus
Sand
Skia
Symbol
Techno
Textile
Times
Times New Roman
Trebuchet MS
Verdana
VT 100
Webdings
Zapf Dingbats
Zapfino

Fonts installed with
Mac System 7

Courier Regular
Geneva
Helvetica
Monaco
Palatino
New York
Symbol
Times

Mac OS 8

All fonts listed above plus:

Charcoal