Terrific post on MyDD.com:

Bush: Social Security Will Be Bankrupt in 1988

by Chris Bowers

From Talking Points Memo:

According to a July 28th, 2000 article in USA Today, back in 1978 when President Bush was running for congress in Texas, "he predicted Social Security would go broke in 10 years and said the system should give people 'the chance to invest money the way they feel' is best."

From the Texas Observer in 1999 concerning Bush's failed 1978 campaign:

According to Gary Ott, who was then a reporter for the Plainview Daily Herald, Bush stopped by the paper's little office "maybe five or six times. He'd sit down at my desk; he was a fun guy. He was very outgoing, very friendly, and we would argue politics since I was a liberal. We'd argue over Carter policies." Bush criticized energy policy, federal land use policy, subsidized housing, and the Occupational Safety and Health Administration ("a misuse of power," he said), and he warned that Social Security would go bust in ten years unless people were given a chance to invest the money themselves."

Back then, he was completely wrong. Now, he is just lying.