Sublime Text 2 - Open CMD prompt at current or project directory (Windows)

1. Click the menu preference > Browser Packages in Sublime Text 2.
2. Create a folder Cmd in the directory opened in step 1.
3. Create a python file named cmd.py with the following code in the Cmd folder created in step 2.

import os, sublime_plugin
class CmdCommand(sublime_plugin.TextCommand):
    def run(self, edit):
        file_name=self.view.file_name()
        path=file_name.split("\\")
        current_driver=path[0]
        path.pop()
        current_directory="\\".join(path)
        command= "cd "+current_directory+" & "+current_driver+" & start cmd"
        os.system(command)

4. Create a file named Context.sublime-menu with the following code in the Cmd folder created in step 2.

[
     { "command": "cmd" }
]

5. Restart Sublime Text.

Now you can open the Cmd prompt at the current directory in the right-click context menu.

Just to expand on TomCaps answer, you can also open the command prompt at the root project folder (as was requested in the question), by changing step 3 to:

3. Create a python file named cmd.py with the following code in the cmd folder created in step 2.

   import os, sublime, sublime_plugin
   class CmdCommand(sublime_plugin.TextCommand):
       def run(self, edit):
           file_name=sublime.active_window().project_file_name()
           path=file_name.split("\\")
           current_driver=path[0]
           path.pop()
           current_directory="\\".join(path)
           command= "cd "+current_directory+" & "+current_driver+" & start cmd"
           os.system(command)
   

The Shell Turtlestein package also has a command for this.
With that package installed, you can type CTRL+SHIFT+ALT+C
(or CMD+SHIFT+ALT+C on mac) to open cmd/terminal in the current file's folder.