C. Moore needed clarification about Microsoft's assorted email clients.
As I write this, there are four commonly-used, Windows-based, local email clients from Microsoft--although only two of them are currently available. (A local email client is an email program installed onto your hard drive.) Their names are often similar enough to invite confusion.
To help limit that confusion, here's a run-down on which is which.
Outlook: Outlook comes with Microsoft Office. Far more than an email client, this is a full personal information manager with a calendar and a task list. The current version, Outlook 2010, looks entirely different than earlier versions.
Outlook Express: Microsoft bundled this an email client with Windows 98, ME, 2000, and XP. You cannot install it into Vista or Windows 7. Despite the name, Outlook Express isn't a subset of Outlook. The two programs have significantly different user interfaces, and entirely different ways of storing messages and contacts.
Windows Mail: Microsoft overhauled Outlook Express so much for Vista that the company gave it a new name. Like Vista--the only version of Windows it was ever bundled with--Windows Mail failed to gain much love.
Windows Live Mail: Windows 7 doesn't come with a mail client, but you can download this somewhat improved version of Windows Mail. It's part of the Windows Live series of free downloadable programs. You can also install Windows Live Mail into Vista.
Contributing Editor Lincoln Spector writes about technology and cinema. Email your tech questions to him at email@example.com, or post them to a community of helpful folks on the PCW Answer Line forum. Follow Lincoln on Twitter.