I saw this in looking for the text of the speech after seeing it on C-SPAN:
"To address the problem, the Bill and Melinda Gates Foundation said it would give 15 million US dollars to the National Governors Association, to be disbursed to states that take significant steps to improve their high schools. The Gates foundation said it had invested 733 million dollars in more than 1,500 high schools - about 8 percent of all public high schools - in the past five years."
source: http://english1.people.com.cn/200502/28/eng20050228_174927.html
Very large portions of that money are in donations of Microsoft Software that are valued at the Full MSRP. IOW, they value a copy of Windows XP at $299 to $2000 and CALs at $59-$199. It isn't real dollars.