Hi,
I forget, which version of the Events module are you using? When you click on History next to 'DotNetNuke.Modules.Events.EventNotification, DotNetNuke.Modules.Events' it will show you just the history for that one schedule item. If you are using 4.0.0 it will show whether it has sent any emails against the appropriate history item. Prior to 4.0.0 it doesn't give any indications sorry.
If you are using 4.0.0 and you see that it has sent some emails, and you don't receive any, this indicates a problem with the mail setup on your site. If you don't see any indication at all, then it should indicate that either no-one has asked for notification, or it is not yet time to be notified.
You can try running the following SQL from Host/SQL. Paste in teh big box and click Execute.
SELECT * FROM EventsNotification
You should get something like the following back:-
NotificationID EventID PortalAliasID UserEmail NotificationSent NotifyByDateTime EventTimeBegin NotifyLanguage
9 24 1 spam@here.com 25/05/2008 07:00:00 25/05/2008 15:00:00 en-GB
It will indicate in the NotificationSent column whether it has been sent or not - it shows a check box which didn't copy above.
Cheers
Roger