you could use a pacifier, but chances are babies arent going to be able to hold it in his mouth all the time and you will be retreiving it a lot. i dont know how your first son was; you dont say, but you might want to stick with nursing for now, your son is so young yet, and im concerned for your milk supply....
i know you are probably exhausted, and would like to be able to get up and do things, especially with another child!! that must be extremely frustrating! i would recommend a sling to help you to have your baby with you while you care for the older child. :) they are awesome. the moby wrap is SUPER comfortable. despite recent news about slings, they are safer than the media is letting on. i was always making sure my son's neck wasnt bent in an odd position, and it was just fine.
heres the thing about breastfeeding too; its a supply and demand system. your infant does need to nurse for comfort; this not only satisfies a deep need within him to know where you are and be have the most connection and comfort as possible, but it also increases your milk supply. a lot of moms end up having trouble with their supply when the non-nutritive sucking isnt allowed. its just as important as the sucking when eating! :):)
so do your best.\
one thing i would highly recommend is to go to a local or nearby la leche league. you might not have one right in your town, but look in neighboring towns. im sure that once a month you could travel to one of these meetings; you will not regret it; they are awesome. :) OR you can just get in contact with a la leche league leader who can give you information and support.
a GREAT book: the womanly art of breastfeeding
good luck and THANK YOU FOR BREASTFEEDING!!!