David Ascher head of the newly formed MailCo has posted plans for Thunderbird 3. The main plan is to increase the already sizable user base (millions) by including with Thunderbird 3 built-in calendar integration (based off of Lighting) much like Microsoft Outlook.  Also to introduce a better search function such as those found in Gmail or Mail.app. In addition to these plans is the goal is to have a final release of Thunderbird 3 by the end of 2008. Here is an overview of David’s plans for Thunderbird 3 in 2008: Goal: To have at public milestone build of Thunderbird…