In general terms, yes, even a specific date is quoted.
See
and
The only reason to stop using it is due to security concerns of the machine is connected to the internet. If a vulnerability arises it won't be fixed after 13/07/2010.
I think there are many more people still using W2k than M$ realise or will publicly admit to. M$ can't be looking too closely at the W2k licences that corporate customers are still using some 8 years after W2k was introduced - I am aware of a number of FTSE 100 companies where new hardware delivered with XP or more recently Vista is being routinely wiped and W2k installed before rollout to employees.
If they make large enough hardware purchases the companies don't even buy the 'new' OS, they just wipe then sell on the old hardware, install W2k on the new and amend their central licence records accordingly - all legitimate and above board.