My hubby works 2 night shifts and 3 day shifts during the week...and we have three little ones (ages 4 and under) at home with us 24/7!
I have to second, third, forth (lol) the idea of using a noise machine (we use one with white noise on it) and/or a loud fan in the bedroom. I would have your clothes laid out the night before in the living room - maybe even some pj's out there for your dh when he comes home - if you are still sleeping. You will both have to work to find a common respect for the situation. For example; he will have to respect the fact that kids are kids and they are LOUD (ha) and at the same time you will have to respect the fact that he does need to get some sleep when he gets home from work. Its SO frustrating for everyone I know! Plus if your little ones know daddy is at home, they won't want him to be sleeping they will want him to be awake to play ;0) so that adds to the frustration!
Do you have a spare room that he could sleep in? Maybe a room thats away from the main living space? Is there any way you could move the computer to another room - even the living room so that you are not 'cut off' from it while he is sleeping? Make any and all changes (no matter how weird or silly they may seem) to help you all cope with the situation better.
When I was pregnant with our now 4 month old my dh would give our older two a bath before he went to work at night - this meant they might have a bath by 2pm!!! but it also meant I wouldn't have to be bending over the tub with my huge pregger belly! lol So it worked for us...others might have thought we were nuts, but oh well right!?!
I would definitely sit down and talk with your dh about things to make the whole transition easier - maybe ask him to just change the baby before he crawls into bed..and in turn there might be things he wants you to do for him before he goes to bed...the best thing is to communicate, otherwise you will be feel so frustrated. And he will eventually get tired enough that he won't even hear you and the kiddos during the day ;0)
Good luck! Let us know what 'works' for you - who knows it might be a great idea for us too :0)