How can this be done? I can't find anything useful via search engines. I understand this will mean that any time passing while this is turned off will not be counted by millis() and any times greaster than 500us won't therefore be picked up by micros(), but I really need to do some tests disabling this interrupt for certain sections of the code then turning it on agaon later. Like doing cli() and sei() but for this particular interrupt only without affecting the ability of other interrupts to run. Thanks.
TIMSK0 is the Timer/Counter Interrupt Mask Register. You could use it To control which interrupts are enabled for which compare/overflow
I can't find anything useful via search engines.
Waste of time. Get a copy of the ATmega328 data sheet, as it is the very best reference. Every interrupt can be individually enabled or disabled by a particular bit in some control register.
See section 15: "8-bit Timer/Counter0 with PWM"