Jesus Christ. Don't listen to some these posts, OP. That's a recipe for disaster.
If you kill the main service disconnect, the lugs coming from the PoCo's side of the panel are still hot and carrying the full 240V @ 200A, or whatever your service is. If you don't know what this means, then really, you need to study up a lot more before attempting or hire it out.
Yeah, I was just reading on how controversial it is to pull power at the meter, plus I guess every state is different.
Related question- the main circuit breaker turns off all the branch circuits below it, at least in my panel. About it are more breakers, mostly 240. Why does the "main" circuit breaker only cut power to the circuits below it, versus, say, all the circuits? I guess that was phased out?
The main service disconnect kills everything downstream from it, which is... everything. If yours doesn't, then you likely have a serious code violation on your hands.
I've done it for remodel and my brewing setup - not a big deal really, especially for installing a breaker, you are never going to be touching the big leads and if you shut off the main power, even that isn't a concern (I guess depending upon your panel age and design) My breakers snap right in, connect the ground to ground bus and nuetral to nuetral bus and connect the leads to the breaker. 10-minute job really.
The "big leads" will kill you if you touch them, even if you shut off your service disconnect. If you want those to be de-energized, then you either need to have a pull disconnect upstream from the meter (unlikely) or have the PoCo pull the meter. My PoCo won't put the meter back in without the city inspector's tag, signature and date taped to panel. If your PoCo is anal, you could very well end up in the dark for weeks while you traverse the permitting process, then get an inspection.
If you want to do this yourself, please permit it. We just had a house fire this past year because I failed to find some unpermitted and faulty electrical work (burried under a foot of attic insulation).
Edit: Perhaps this will help show the seriousness of this. Here's pictures of what it looked like the morning after the fire department gutted the attic above my living room. I'm extremely lucky I didn't lose the whole house and nobody died.
Total cost was about $45,000 and counting.