The project seems to be no longer developed. Last version, ClipX 220.127.116.11 beta 7, released in July 2008, can be still downloaded from the official website.
ClipX is a tiny clipboard history manager. It is sweet, it is free, use it. You can use the system tray icon to restore your old clipboards and use a hotkey to paste them directly inside your favorite editor. Plugins are available to add functionality such as saving images and marking items as permanent.