Ok, easy answers....
First NetSend. Make sure the Messenger service is turned on at both the sending and receiving computers. Windows 2003 has this turned off by default.
For Printer notifications, make sure you either have selected the Printer recipient to be notified within the Job properties (on the notification node) or from Alert Category setup by assigning the printer recipient to the alert category.
The difference in the two above methods is that a per job notification will only send notifications to the recipients selected in the job properties, and it will only send notification when the job completes (due to success, failure, with exceptions, or cancellation.) Assign the recipient to an alert category will trigger a notification to that recipient every tiem that alert category is triggered, regardless of what job caused it. Methods are all a matter of preference however.
A few other things to check, ensure that on the recipient's properties screen you do not have a schedule which limits the alerts allowed to certain times, as well as makingsure the settings "Limit the number of notifications sent" are valid, if you have the option enabled.