Switchtags.vim is a project mainly written in Vim Script, it's free.
Switch tags option automatically between different projects
This is a mirror of http://www.vim.org/scripts/script.php?script_id=1344
When edit files that belong to different projects with different tags option settings at the same time, it's annoying to switch tags option manually. This plugin can switch tags option automatically according to the buffer's file full name.