Where you mail the completed IRS for 941 form depends on what state you live in, whether you are including a payment, and other factors. For details of where you should send the form to, visit the IRS site at the Related Link.
http://www.irs.gov/file/article/0,,id=111163,00.html
where to find 941 for 2012 and Schedule B for 2012
There are several addresses; please see the link below.
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html
http://www.irs.gov/file/article/0,,id=111163,00.html