I know this thread is a bit old, but it's the first one that comes up when you google for how to change menu bar item orders.
In Leopard, (I'm on 10.5.6), you can change the order of how menu bar apps appear by simply loading them on demand as a user created app.
Firstly, you need to remove the apps you want to organize in the Accounts > Login Items preference pane. You also need to make sure they're not being loaded from the Dock, so right click the dock icon and disable Open at Login for each specific menu app. I'd recommend Logging out and back in to make sure they're not loading automatically at this point. If a particular app loads, it's probably a setting in the application itself, dig around the preferences for that app and disable it.
From here, open up Script Editor and create a script similar to this.
activate application "coconutWiFi"
delay 1
activate application "Ejector"
delay 1
activate application "Bokeh"
delay 1
activate application "PTHVolume"
delay 1
activate application "Dropbox"
delay 1
activate application "WeatherDock"
The app at the top, in this case "coconutWiFi" will load first and thus be placed in the right most position available. In the same regards, "WeatherDock" will be the left-most app on the menu bar.
Save the script (I called mine -- MenuBarLoader), change the File Format to Application, and leave all other options as is. For organization, put the newly created application in the Applications folder like any other app.
Now go back to your Accounts > Login Items preference pane, drag and drop your newly created MenuBarLoader app in the Login Items field, and click the checkbox to Hide the app. Log out and back in to give it a test run.
There you go, you now have menu bar apps loading in a specific order, and thus, showing up in a specific order. Keep in mind, you can not (atleast to my knowledge) make applications load more right than the Apple icons (spotlight, airport, bluetooth, etc.) Two exclusions that I know of are MenuCalendarClock (which loads in the clock's default position) and iStat (which can be setup to load just to the left of the clock by simply CMD-click & dragging it in the spot you want it in.)
