dautley
Android Expert
I'm seeing rumors that a 6.7.235 ICS leak is out but supposedly it's locked down like ICS was on the Razr and you can't FXZ back to 902 so if you find it and want to flash it be warned you could be stuck if it's not the Official OTA.
http://www.droidhive.com/forums/index.php?/topic/1415-ics-404-leak-67235/
http://www.droidhive.com/forums/index.php?/topic/1415-ics-404-leak-67235/

Anyways, usually when an OTA comes out you'll get a gray alert box that pops up and tells you there is download available and there is usually an option to accept it or to be reminded later. I'm pretty sure they're always optional I can't recall one where you had to accept it right that moment. And yes to get the update alert again you would go into the system updates menu and tell it to check for updates which would trigger it to pop up again.