Download of Thunderbird_Portable_1.5.0.7_en-us_PRERELEASE.exe (Thunderbird_Portable_1.5.0.7_en-us_PRERELEASE.exe ( external link: SF.net): 7,679,089 bytes) will begin shortly. If not so, click link on the left.
The Mozilla Thunderbird®, Portable Edition project is now part of the PortableApps.com project: http://sourceforge.net/projects/portableapps