Download of portable_thunderbird_1.5rc1_en-us.zip (portable_thunderbird_1.5rc1_en-us.zip ( external link: SF.net): 8,314,313 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