Textpander, a great new Mac OS X utility, allows you to type your most commonly used phrases by entering simple abbreviations. Want the current date? Just type "ddate", one of the default shortcuts. Textpander automatically expands it to the current day, month, date and year. Do you often use stock salutations in your e-mail? Textpander makes it easy to design your own and assign a shortcut sequence.
You can even use Textpander to correct common typos. I created a shortcut called "teh", set it to convert to "the" and instructed Textpander to match the case I typed by using the "Adapt Content" option. Now when I type teh, Textpander automagically corrects it to the. Very convenient!
You can enable and disable Textpander from its System Preferences panel. The easy-to-use interface also allows you to add, update and remove shortcuts, which it calls "Snippets". Textpander is free, for Mac OS X 10.3.9 or later.
Textpander [via Slacker Manager]