If you are a CPA firm conducting governmental audits - you should join the Government Audit Quality Center. The AICPA does a nice job of presenting resources for Single Auditors.
For instance, if you Google OMB Circular A-133, a huge number of OLD documents pop up. Same with the Compliance Supplement. But the AICPA has put the latest here:
Nice. To be a member, you have to pay and qualify. But, so far, from my experience, it appears worth it. Just hearing Frank Crawford updates alone is worth the money. He is such a great teacher.