Email script/program similar to gmail's threaded conversations?

[Wojtek]

Is there any email script / email program in existence that has a gmail-like email threading inerface?

Both Outlook and Thunderbird fail miserably in their threading capabilities.

Anything else?

[engineerroy2008]

Socketmail.com try this it is having features you need also the mail enable can support threading

[SiberForum]

As far as I know you can gmail interface for the non gmail emails

[Wojtek]

Yes that's what I'm doing currently but for privacy reasons the boss doesn't like me linking the company's support email to gmail's servers.
Outlook is okay, but not when you get dozens of emails everyday and you have to keep track of if it was replied to or not.

[~ServerPoint~]

Thunderbird have lovely interface and security issues