The reason you don't get reminders from Now Up-to-Date & Contact when using 10.6 (Snow Leopard) is because the Quickday menu item is not compatible with 10.6 and it is the process that controls reminders. Every time Apple releases a new OS, they break 3rd party menu items. We are still reviewing the possibility of updating QuickDay and QuickContact to work with Snow Leopard, but the effort involved would not be insignificant, and all our current development efforts are focused on Now X currently.
Sean Boiarski
Product Manager, Now Software