The Terminal Here plugin provides a Contextual Menu Module for the Finder in OS X. This CMM provides a popup menu item when right clicking on a directory or file with the option to 'Open Terminal Here'. When used on a file, it acts as if you used it on the directory the file is in.
When selected, Terminal.app will be launched if it is not already running, and a new window will be opened and a cd command issued to switch to the appropriate directory.
This is primarily intended for those who do a lot of UNIX style work and really need the Terminal.app to do it.