In a possibly interesting turn of events (for those who care about such things - I obviously can't buy US bonds...) the Communications of the ACM (July 2003) is reporting that the US Treasury will stop selling paper bonds in 2004 'requiring all purchases to be made exclusively online'.
Quite how this will be accomplished, except with payment cards, is unclear!
[This message has been edited by NickW (edited 08-08-2003).]