Thunderbird has been updated to v1.5. “Thunderbird v1.5 introduces several new features including a software update system, spell check as you type, built in phishing detector, auto save as draft, and support for deleting attachments from email messages. Message filtering has also been improved with new filter actions for replying and forwarding. Saved search folders can now search folders across multiple accounts.” The release notes are available here. Read the Favored Freeware entry for Thunderbird here.