Although not new, CNET has a great overview of getting set up with GPG, Enigmail, Thunderbird and Gmail to start encrypting your Gmail messages.
Of course this will work with other web-based email, like Hotmail, Yahoo! and AOL, you just have to use the right configuration options to link your web-based mail to Thunderbird (with POP or IMAP.)
Of course this will work with other web-based email, like Hotmail, Yahoo! and AOL, you just have to use the right configuration options to link your web-based mail to Thunderbird (with POP or IMAP.)