How do I configure which programs autostart when connecting to the internet?
Without root you only have the control the app developers give you: If an app allows you to configure this behaviour, you can do so -- otherwise you can't.

If your device were rooted, on the other hand, you'ld have several possibilities:


Use DroidWall to define which apps may use 3g, which Wifi, which both, and which none (1st pic below)
Use LBE Privacy Guard to do the same, and more (2nd pic)
Use Autorun Manager to disable certain listeners of apps, so they no longer get informed about network changes (3rd pic; experienced users only!)


  

This is just a selection, and thus the list is very incomplete. As you already wrote your device is not rooted, it doesn't make sense to put all those details here; it's just to give you an idea what would be possible with root, not to elaborate all options ;)