Here are some helpful posts about credible witnesses. Not all states allow credible witnesses, and the rules are state specific.

Credible Witnesses from A to Z
http://blog.123notary.com/?p=452

Notary Public 101 (covers many Notary issues, but not Credible Witnesses.)
http://blog.123notary.com/?p=19493

Credible Witnesses — the process explained
http://blog.123notary.com/?p=16695

Credible Witnesses, the ins and outs
http://blog.123notary.com/?p=19634

Credible Witnesses
http://blog.123notary.com/?p=18911

See our string on Credible Witnesses
http://blog.123notary.com/?tag=credible-witness

Credible Witness protection plan
http://blog.123notary.com/?p=18831

Where do credible witnesses sign the journal book?
http://blog.123notary.com/?p=2508

How much can a Notary charge for a credible witness?
http://blog.123notary.com/?p=2700

Credible Witness requirements
http://blog.123notary.com/?p=2464

What is a Credible Witness notarization?
http://blog.123notary.com/?p=2408

Oath of two Credible Witnesses
http://blog.123notary.com/?p=2405

Types of witnesses in the Notary profession
http://blog.123notary.com/?p=5664