Navigate to a folder that you know is in your PATH, the simplest will most likely be system32. Simply run system32 and explorer will open there.
Create a new file, call it subl.bat and edit it like this:
@echo off start cmd.exe /c "C:\Program Files\Sublime Text 2\sublime_text.exe" %*
You may need to change your path to the sublime_text.exe.
Now you should be ready to:
cd path/to/project subl .