The Per Page Sidebars (PPS) plugin allows blog administrators to create a unique sidebar for each Page. No template editing is required.
Some themes allow you to chose different sidebar layouts on each page. Sometimes these themes rely on a Primary/Secondary Sidebar configuration rather than a Right/Left sidebar convention. This may lead to confusion when the parent displays two sidebars and the child only displays one. This plugin replaces the sidebar by name not by position. In a 2 column layout, the only sidebar is by definition the "Primary" sidebar. Replacing a "Secondary" sidebar in the parent page will not alter the appearance of 2 column child page if the "Secondary" sidebar is never displayed.
Currently only one sidebar can be replaced per page. If you wish to replace multiple sidebars per page, leave a commment and I may add this feature.
YES! Version 2 of the plugin allows sidebars on posts. However, custom post types are not yet supported. If this is a disired feature, leave comments requesting it and I can add the feature fairly easily.
A user can only replace a sidebar on a page if their role has the edit_theme_options capability. A user can edit a page that has been assigned custom sidebar and that custom sidebar will not be dropped. A user without the edit_theme_options capability simply cannot turn that functionality on or off.