- Open HAM (the application manager that's installed on your phone from the beginning). It's called 'App manager' in the main menu.
- Click on the title bar at the top of the screen.
- Press on the button called 'Application catalogues'.
- Open the items in the list, one by one.
- For each, check the 'disable' box at the bottom of the screen that pops up.

Done.

HAM will not see the repositories so will not be able to update. From my experience this prevents you from being able to do apt-get.

Before you do the above, you might like to install Faster Application Manager (FAM). This does not update software automatically but does allow you to install and update programmes when you choose - it can operate when HAM has all repositories off.