Sidebar is a major feature in Windows Vista which boosts your personal productivity by providing instant access to gadgets—a wide variety of engaging, easy-to-use, and customizable mini-applications that offer information at a glance and provide easy access to frequently used tools. For those who want to enjoy the Vista look alike sidebar in Windows XP please check these links:

Thoosje Vista Sidebar
thoosje has released a new version of his nice looking sidebar for Windows XP users which looks very similar to Vista's sidebar.
Download: Thoosje Vista Sidebar
View: Screenshot

M!W sidebar
A nice looking sidebar gadget created by M!W with lots of features
Download: M!W sidebar
View: Screenshot

Yahoo Widgets Sidebar
SidePanel is a skinnable Widget made by Richard Kyle which allows users to add a panel to their screen so that Widgets may be placed on top of it. Similar to the Windows Vista Sidebar.
Download: Yahoo Widgets Sidebar
View: Screenshot

AveDesk Sidebar
A simple guide to use AveDesk for adding shadow under Taskbar. You can do the same for adding Vista style sidebar to your desktop.
View: The guide

Samurize Vista Sidebar
Windows Vista style sidebars for Samurize users. Samurize is an advanced system monitoring and desktop enhancement engine for Windows 2000/XP/2003.
Download: Samurize Vista Sidebar
View: Screenshot

Original Vista Sidebar Ported to XP
The original Windows Vista sidebar and it's gadgets have been ported to Windows XP (unofficially) but the sidebar.exe is being treated as a warez so distribution is not permitted here.
For those who has Vista, here's a small guide about how to get it running it on Windows XP.
Download: Patch and the guide
View: Discussion thread 1
View: Discussion thread 2

eXP Sidebar
eXP is a sidebar for Windows XP which is written in C#. It imitates the Vista sidebar's look & feel. This program is in developing stage right now.
View: eXP sidebar

Desktop Sidebar
Desktop Sidebar provides you with instant access to the information you most desire by grabbing data from your PC and the internet. The result is a dynamic visual display you configure and control. Lots of plugins/panels and skins make it one of the most populat sidebar app.
Download: Desktop Sidebar
View: Screenshot

SmartBarXP
This sidebar can be configured to display interactive panels known as 'panes'. These panes include media players, slideshow and image viewing panes, a virtual desktop manager, and live news, weather and stock feeds to mention but a few. The panes can be repositioned on the bar, and scrolled if the bar becomes too full. The bar can also be host to extra sections, which include a recycle bin, explorer shortcuts, and taskbar replacement sections (start button, taskbar buttons and system tray sections).
Download: SmartBarXP
View: Screenshots

SpyderBar
From the makers of StyleXP, this sidebar is highly responsive, intuitive, and skinnable. Although feature packed, it remains lightweight with an executable size of just 1 MB. It is the ONLY user interface of its kind (more on this below). You can dock, undock, and even throw around panels.
Download: SpyderBar
View: Screenshots

Codename: Dashboard
Codename: Dashboard is an application that docks to the side of your screen and acts as a host for interchangeable components. Through these components, you can have access to any information you want on your screen, all the time.
Download: Codename: Dashboard 2.0
View: Screenshot

Google Desktop Sidebar
It surely doesn't look like Vista sidebar but if we are talking about the sidebars then this program should be mentioned here. Google Desktop supports gadgets now. Gadgets are mini-applications which can be anything from games to search tools to media players, and they can be any shape and size use a weather globe to show you the latest forecast.
Download: Google Desktop
View: Screenshot

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