If you're using EndNote and you want a Harvard output style which conforms to that of the Style Manual for Authors, Editors and Printers, you can download this one from the University of Queensland library website: uq_harvard_2002_v8+.ens
Save the style into your EndNote styles folder (typically C:\Program Files\EndNote X4\Styles ), then open your Style Manager in EndNote (Edit | Output Styles | Open Style Manager) and tick it so that it appears on your drop-down list of favourite styles.
The University of Queensland Library also provide additional instructions to help you use the style correctly, and it would be wise to consult this to ensure that you produce properly formatted Harvard style references from your EndNote library.