I don't think reports can be automatically mailed. However, you could set up a filter-type alert for each item type; the alert would run once every weekday morning and simply mail a list of open items to the respective [ASSIGNED TO] users. If you click the "Send one email..." option when defining the alert, the items will be bundled per [ASSIGNED TO] user, so that each user gets only a single mail in the morning (instead of one mail for each item).