One of the best freeware utilities available for Outlook has just gotten better. PocketKnife Peek makes it easy to view message headers and source. It now supports reply in plain text and view attachment information, including names (with extra spaces removed) and file sizes of attachments sent in zips.

Other features of PocketKnife Peek include Reply to some, which presents you with a list of the names the message was sent to (or use it to see and easy to read list of everyone it as sent to). It also has Forward and Forward as attachment options.