I assume you're scheduling the report in BusinessObjects or Crystal Reports Server. There are two ways I know of to do this.

The first way is to create a formula that will cause an error (such as division by 0) if there is no data. This will cause the schedule to fail and nothing will be sent out. The problem with this is that you still have to look for failed reports and determine why they failed to make sure that you're not missing a problem other than that there was no data.

The other way is to use a Publication. You don't have to use the bursting functionality in a Publication - you can schedule it to go to a specific list of people. Under Additional Options>>Delivery Rules you can tell it to only deliver when the report contains data.

-Dell

If your output is excel, you can use a blank report header and in section expert check 'New Page After' in Paging. In the CMC on the Recurring schedule, use Page Range 2 to 999 on the Formats tab.   And (of course) turn off any failure notifications.