Not directly, but you CAN see the items after a sync to the private Mailboxes. This is why:
Add2Exchange creates an information relationship between those public folders and the personal folders, and the personal are the ones the smartphone can look at. When you do set up that relationship, A2E copies all the items or all the items within the date range for Calendars to the private folder. You can set the relationship up to be able to edit the copies the user gets and/or delete them. That is a bidirectional relationship because the information changes for the ones created in the public go both ways. You can also set the relationship up to be unidirectional, when the public copied information is for view only purposes, where changes to the destination items are overwritten from the source.
To be complete, if you want anything created in the private folder to be copied to the public, as in an aggregated group calendar, for example, you would need a private to public relationship. Tip: for a calendar relationship, you could use the auto place the users initials in the subject of the appointment so people know where it came from.
Incidentally, for a Blackberry, it only has one calendar so you have to make the relationship to the default calendar. Iphones and Palms can have multiple calendars sync so you can create a new Public copy of the calendar in the private mailbox under the default calendar and make the relationship there.