I just updated my address with all 3. Faxed in a copy of my Driver's License (showing the correct address), copy of my SSN card, and for EX include a copy of a recent utility bill showing the correct address. It was updated on all 3 CRAs the next day.
Nothing fancy, just a FAX cover sheet produced out of MS Word, and no signature needed. They want the docs to prove it, but they'll usually act quickly.