bind "MOUSE2" +bluebot_aimbot
bind "MOUSE2" bluebot_aimbot_toggle
You also need to access the menu to make sure the aimbot aims on key. (In this case, mouse2) You can have aim on mouse1 and aim on key active at the same time without problems. Personally I don't like toggle, but some people do.
Edit: On a side note, I was thinking about having a version of bluebot that would get the latest version from the SVN and run it directly. This way you would always be using the latest version of bluebot and you would never have to manually update your client. You could also have the option of downloading the file from the SVN, if you wish.