So I bet you would not be surprised if I told you my wife Louise handles all that huh?
As I understand it earnings, as long as used for appropriate stuff for education are not taxed. Here is a quote from the IRS ...
A. Earnings are not subject to federal tax and generally not subject to state tax when used for the qualified education expenses of the designated beneficiary, such as tuition, fees, books, as well as room and board. Contributions to a 529 plan, however, are not deductible.
Here is the IRS Q&A site for 529's
IRS 529 Q&A