Before you begin make sure you entirely read the tutorial.
1. Download Android SDK and USB drivers
Download the latest AndroidSDK from Google and extract the AndroidSDK.zip file to C:\AndroidSDK.
Download and install HTC Sync from HTC (HTC Sync is not required for ADB but it's the easiest way to install usb drivers).
If you are using HTC Hero and Microsoft Windows 7 (and you experience problems with driver installation) you have to follow this procedure to install usb drivers and HTC Sync.