Synchronizing Passwords

Does anyone have a good procedure on password synchronization.
In our NT 4.0 domain, we have laptop users passwords expire after a few months, unfortunately, using an ISP intranet solution they do not get the warning of the upcoming expiration. So they have to logon to our RAS and try to change and synch their passwords with their cached passwords on their laptops.
Is this the best way? I was just wondering what everyone else’s experience was.
We’re running Win2K and XP clients out in the field.

Thanks