The labels on a pie chart in SQL Server 2005 Reporting Services (SSRS) are very ugly. They just get thrown over the chart by default and they all overlap. I hate it!
This MSDN page tells us how to fix it http://msdn.microsoft.com/en-us/library/ms156263(SQL.90).aspx
To change the position of point labels in a pie chart
Using Report Designer, create a pie chart. For more information, see Working with Chart Data Regions.
In Layout view, right-click the chart, and then click Properties.
On the Data tab, in Values, and then click Add or Edit to open the Edit Chart Value dialog box.
On the Point Labels tab, clear Auto, and then select a button other than the center button.
To set options on this tab, Show point labels must be selected.