Git-file.vim is a project mainly written in Vim Script, it's free.
open any version of a file in git
This is a mirror of http://www.vim.org/scripts/script.php?script_id=2185
Allows for opening
You can open a file from the shell:
vim HEAD~10:filename
or from inside vim:
:e branch:filename
:sp tag:filename
you could even check what changed between the current edits and another revision:
:diffthis
:vsp HEAD:%
:diffthis
but that's what gitdiff.vim (vimscript#1846) is for.