Scott Morrison of Indev Software 
(producers of the MailTags and Mail Act-on plugins) has released a souped-up version of the miniMail plugin, which he recently acquired from Olive Toast Software.
miniMail 2.0 retains all the goodness of the original–the ability to minimize Mail.app’s interface like you can in iTunes–but adds more features and flexibility.
The minimised interface is elegant and efficient, as you would expect from the developer of MailTags:
It is also fully integrated with Mail Act-on, allowing you to use the same keystrokes to file messages away quickly.
The plugin’s Preference pane offers options to control which mailboxes it monitors, text size inside the minimized interface itself and how it should expand again when double-clicked (to the mail mail.app window or a single message window):
The Preference pane also controls miniMail 2.0’s new feature–multiple mini viewers.
You can now open a Message Viewer for a number of individual mailboxes and minimize them to keep track of new messages in particular accounts or even RSS feeds.
Here I am monitoring my work email in one miniMail window, my Hawk Wings email in another (one canny doctoral student sends his emails to both!) and the network status RSS feed of my ISP:
Very handy for keeping focus on important things whilst filtering out the rest.
miniMail is shareware (USD 12.95) and is available from Indev’s web site . Registered users of MailTags and Mail Act-on qualify for a USD 4 discount.
Saw this last night – Indev is also part of the http://www.onefingerdiscount.com event that is going on until this Friday.