Snail Mail's primary function is to quickly address and print single or multiple envelopes based on entries in the Mac OS X Address Book database, but it also allows ad-hoc manual entry of addresses directly onto the envelope.
Batches of envelopes can be based on Address Book groups, or ad-hoc selections of addresses. Snail Mail can print USPS barcodes for more efficient mail handling. Snail Mail provides for different default text attributes (font, colour, etc) for different parts of the address.
Snail Mail also includes a Plugin for Mac OS X's Address Book application so that you can choose to print Snail Mail envelopes directly from the Address Book, and uses Mac OS X 'services' to print any selected text from any other application to an envelope quickly and easily.
Mia for Gmail (was Notifier Pro for Gmail) is a desktop Gmail client which sits politely in your menu bar.
