Managing comments on WordPress is the most important task for bloggers and doing it efficiently is more important. Normally for approving comments in WordPress webmasters log in to their WordPress dashboard and approve, deny and manage comments, but there are lot of applications and plugin which lets you do this directly from your desktop and you need not log in to your WordPress dashboard every time. I love to use this kind of tools as they are quite user friendly and easy to manage comments from desktop.
Here is name of few tools which will help you to deny, approve and manage comments from your desktop :
WP- Comments-Notifier
This is an open source application which is developed and written in QT/C++ and its a simple application, which lets you deny, manage and approve comments from your desktop and it works well with wordpress MU too. It has pop up notifier which inform you about the latest comment and you need not check your WordPress desktop everytime.
All you need to do is just download this and run the application and perform the desired instruction from this page.
Desktop Comment Moderator Plugin
This is a plugin which lets you deny, approve and approve comments from desktop and it is built on Adobe air platform. This lets you see unapproved comments, accept , delete, spam comments and at the same time see gravatar of user who has posted the comment. This is quite user friendly plugin which takes minimum effort in installing and managing. I would say this is a must for every blogger to manage comments efficiently and effectively.
For this application you need to have wordpress 2.6.2+ and Adobe air and below is the installation steps :
1. Download the plugin from here and unzip the content.
2. After unzipping it install it on the WP-content-plugin. You will have a moderator name in this.
3. You now need to activate the plugin from admin panel.
4. Once you activate this plugin, you need to follow the instruction for installation of the desktop client.
We hope these desktop applications help you to deny, approve and manage comments from desktop in WordPress. Do tell us that in below comment.

I was looking for tools that allow approving comments without logging in and came across your site. Will try these plugins out. Thanks for sharing.