Mark Jaquith

Some WordPress sites have problems with scheduled posts, where they don’t get published at the right time. Instead they appear as “missed schedule”. This plugin monitors scheduled posts, and makes sure that doesn’t happen.

Scheduled Post Guardian

Watches over scheduled posts, and makes sure they don't miss their scheduled time

rickacc

Linked Future Posts Widget acts very much like the upcoming posts widget by displaying 
scheduled posts instead of published ones, but includes a link to each post (using slug/post name). Requires WordPress 2.8+
Use this plugin in conjunction with the Future plugin from Marion Sudvarg to create a Post Grid of scheduled events and a list of scheduled 
events on the post page. Events that change from scheduled to published status will automatically be removed from the grid and list.
Linked Future Posts Widget is a derivative of the Upcoming Posts Widget plugin created by Aaron D. Campbell.

Linked Future Posts Widget

A widget that displays a list of scheduled posts with links to the posts.

Scheduled Post Guardian vs Linked Future Posts Widget