[yters]

Emacs has VIPER mode, which uses the Vim keybindings in Emacs.

Haven't tried learning the keybindings yet myself, and I've heard VIPER isn't the complete Vim.

[nocman]

If you want something closer to Vim keybindings in Emacs, try vimpulse:

http://www.assembla.com/wiki/show/vimpulse