Windows 7 supports new features including easy Theming & Desktop Background Slideshow. You no longer need to patch system files or use 3rd party software to create and install themes in Windows 7.
A new file format, .themepack, has also been introduced with Windows 7 to help users share themes. A .theme file is basically a .cab file. It enables you to change the appearance of certain desktop elements. You can create or modify a .theme file in two ways:
- Modify personalization or display settings in Control Panel and save the settings as a .theme file. See your Windows Help for instructions.
- Create a .theme file manually for a greater level of control over the details of your theme.
To make your theme available to users of your application, you must supply your .theme file, as well as the background picture, screen saver, and icons files. You can do this with a theme pack.
A theme pack contains following things:
1. Wallpaper with or without Slideshows
2. Window color
4. Screen Saver
Do note that from the LHS pane, you can also change the Desktop Icons & Mouse Pointers.
To create a theme pack:
Right click on your Desktop > Personalize.
Apply the default theme. Click on Desktop wallpapers. Select the wallpapers or browse to the folder which includes you desired wallpapers. Set the Picture position – usually Fill or Stretch. Confirm the time interval for the Slide show and if you want it to shuffle. Save changes.
Next Choose the Windows Color, Sounds and Screen Saver if any.
You will see it as a Unsaved Theme. Click on Save Theme and give it a name. Next right click on this theme and select Save theme for sharing. Give it a name and save it a .themepack file.
To install the theme simply double click on the theme pack.
How to extract wallpapers from Windows 7 themepack may also interest you.
Advanced read : MSDN.
UPDATE - 5th June 2009: Addl read on E7 Blog.