CNET

Mini-Tutorial: Re-installing Apple applications from a Mac OS X disc/update package using Pacifist

For various reasons, applications originally installed by the Mac OS X Installer disc (DVD or CD) -- Mail.app, Activity Viewer, etc. -- can become unusable. This can occur due to user deletion, ...
CNET

Re-installing individual Apple applications from Mac OS X media (Safari, Mail.app, etc.)

In many cases, re-installing applications from original media or download packages can resolve problems with launching, improper behavior and other issues that are caused by file corruption or ...
Ars Technica

How to secure your e-mail under Mac OS X and iOS 5 with S/MIME

Mac OS X Mail has supported S/MIME e-mail signing and encryption for many years, and iOS 5 now brings this feature to the iPhone, iPod touch and iPad. Here's how to use it.
Cult of Mac

Easily Track Your Packages In Mac OS X Lion Mail [OS X Tips]

Tracking shipped packages is fast and easy in Mac OS X Lion due to Apple Mails tight integration with WebKit. It is also one feature that Apple brought to Mac OS X from iOS that I actually like.