Apple's Mail program has improved dramatically with each new iteration of Mac OS X; the version of Mail included with Leopard is no exception. Still, there are features heavy users of e-mail miss, and ways in which you may find even the latest Mail wanting.

This week on Mac Gems, I'm going to cover some of my favorite add-ons and plug-ins for Mail--software that gives Mail new features, fills holes in its functionality, and generally makes it a more effective way to communicate.

I start today by revisiting Leopard-compatible updates to Mail tweaks I've already covered; later this week I'll show you a number of new add-ons.

LetterBox 0.22. One of the most popular Mail add-ons I've covered is LetterBox, which lets you move the preview pane from the bottom of Mail's window to the right-hand side -- a setup that uses the space on today's widescreen displays more efficiently (and one that's available on many competing email clients). Having the preview pane on the right also lets you preview more of each message, as well as see more messages in the current mailbox or folder. The current version of Letterbox works with Leopard's version of Mail; in addition, unlike the version I covered back in 2006, Letterbox now lets you easily switch the preview pane between the bottom and right-hand positions. (The developer is currently working on an update that will provide a two-lines-per-message display in the message list, so you can see more information about each message.)

Mail Act-On 1.3.3 Public Beta. Back in November 2005, I reviewed Mail Act-On, a nifty plug-in for Mail that lets you invoke mail rules using the keyboard. This means that anything you can do with a rule in Mail--move, copy, forward, redirect, reply to, or delete a message; set the color or read/flagged status of a message; or even run an AppleScript--you can do via the keyboard using Mail Act-On. The current public beta, still in early development, lets Mail Act-On work with Leopard, although it adds no new features.

Mail Scripts 2.8.3. Way back in 2004, I noted Mail Scripts, a set of AppleScripts for Mail that let you accomplish otherwise-difficult tasks. For example, you can use Mail Scripts to add all recipients of the current message to your address book, archive messages for backup or transfer, switch between SMTP servers, create rules based on the current message, remove duplicate messages, schedule messages to be sent at particular times, immediately send all Draft messages, open all mailboxes with new messages, apply rules to Sent messages, export contacts, and conduct complex searches of your address book. All these scripts now work with Leopard.

For more Mac news, visit Macworld. Story copyright Mac Publishing, LLC.