It's supposed to be in the 'Nokia Catalogue', the one that if you go to the application manager/tools/application catalogue menu says 'Nokia Catlogue' and Details says 'http://catalogue.tableteer.nokia.com/certified/' and 'Distribution: bora' and 'Component: user'

EDIT: If you don't find it it could be that you have it installed already.. in the application manager, select installed applications and look for mnotify. If it's there (instead of in the list of installable programs) then go to control panel, select Navigation, Status and tick the right box in the list.