I'm not exactly sure what you mean by SOX compliant. I understand that SOX is all about corporate accountability. So at the end of the day it will be your company's policies and procedures (and proving you follow them) that determine your SOX compliance. Alfresco can be a valuable part of your IT solution by providing features for example security, auditing, workflow, document management, the list goes on…
But at the end of the day it will be your company's policies and procedures that ensure SOX compliance not the IT systems.
Alfresco is committed to go through DOD 5015.2 accreditation this Summer. Are there any other standards you are specifically interested in?