You may receive winmail.dat files from senders who are using Microsoft Outlook. Winmail.dat contains attachments and rich-text messages, and not all e-mail clients can recognize its format. Winmail-Extractor-Lite is a solution to extract and save the contents of winmail.dat files. You can open a Winmail.dat single attachment file in external applications.
Mia for Gmail (was Notifier Pro for Gmail) is a desktop Gmail client which sits politely in your menu bar.