Actually, Buffet and Gates are good friends. Gates is on the board of directors of Berkshire Hathaway, the company mostly responsible for Buffet's recent profits.
Buffet recently gave 30 billion to the Bill & Melinda Gates Foundation charity.
"In June 2006, Warren Buffett gave approximately 10 million
Berkshire Hathaway Class B shares to the
Bill & Melinda Gates Foundation (worth approximately USD 30.7 billion as of June 23 2006; making it the largest charitable donation in history. The foundation will receive 5% of the total donation on an annualized basis each July, beginning in 2006."
source:
http://en.wikipedia.org/wiki/Warren_buffet