In the japanese media there was an official "nothing happened" on the first day around 10am, except for a few train ticket vending machines. The day after they started to mention that problems had happend in nuclear power plants (which are under thourough scrutinity since the accident a few months ago in Ibaraki prefecture), but it was clearly mentioned that the problems did not affect the power plants themselves but mostly administrative systems...
I'm pretty sure that a few years from now, we'll be informed that in fact such and such company/gvt agency had really a major problem but for security/publicity reasons it was covered up... :-)
A happy y2k !
Jean Christophe Helary