The address you mail your tax return to changes depending on what type of tax forms you are sending. The IRS website can assist you in choosing the correct address. http://www.irs.gov/individuals/index.html
You will need to send your Federal Income Tax to the Internal Revenue Service for your state. You can get the address from the post office or on the directions that come with the forms. If you file on line you won't have to mail it. It's free so why not!
You will have to mail your federal tax return to the main office for the IRS. The address will depend on where you live. For more info, click on the state that you live in at; http://www.irs.gov/localcontacts/index.html