Hello there, If your son turned 24 in 2007, then he is too old to meet the dependency requirements of "qualifying child". He may however be a "qualifying relative" for dependency purposes, but he would have had to have had less than $3400 in gross income for the year.
If he does not meet the requirements for a dependent, they you may not take any tax related benefits for his education. He may claim himself and take either an education deduction or credit, whichever benefits him the most.
If you need more information or clarification, please let me know.