This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
SAX is just for parsing XML - you can't use it to change XML (unless you want to write code that recreates the complete XML file).
DOM can be used, as could any of the other XML object models (XOM, JDOM, dom4j). See e534 to e538 for examples of how to work with attributes in DOM. See this for how to obtain a DOM Document from an XML file in the first place.