I'm a huge fan of Google Apps which includes customized Gmail, Google Documents and Spreadsheets so every time I setup a hosting account I always configure Google Aps for customers. Google does have their own little tutorial pages but I've found them to be dissappointingly short on details specifically regarding the "prevent spam" option. I want to prevent spam! I don't want anyone emailing other companies spoofing my URL, that just sucks for everyone.
Below I have coppied the basic setup information for Google Apps on Godaddy or Sustainable Online Solutions ver batim from Google's help pages as follows: