QShowpost is a command line utility for examining the queue levels of a Postfix server How many messages are delayed? How many are in the Hold Queue? QShowpost will give you those answers.
It is a compiles tool using Qt4 in C++. It supports multiple instances per box - you simply edit the config file to add a new instance and define where it is. It can run in one-shot mode (default) or, if passed a numeric option, will run continuously updating every number of seconds passed into it.
It now resides on github at [QShowpost Repo]