Download the Appropriate File:

Bitmap-BMP (preferred)
800x600
1024x768

JPEG
800x600
1024x768

To Download:
PC - right-click a link, select 'Save Target As'
MAC - click and hold, select 'Save Target As'

To begin using the wallpaper, follow these steps:

For Windows
1. Download the file above
(If you are unsure which file to use, start with the 800x600 bitmap.)
2. Save the file to your hard drive and remember the location
3. Go to 'Start'->'Settings'->'Control Panel'
4. Double-click 'Display'
5. Select the 'Desktop' tab
6. Click on the 'Browse' button (located on the right side)
7. Browse to the 'pin800x600.bmp' file you just saved to your hard drive
8. Click the 'Open' button
9. Make sure the 'Position:' is on 'Stretch'
10. Click 'OK'

For Macintosh
1. Download the file above
(If you are unsure which file to use, start with the 800x600 JPEG.)
2. Save the file to your hard drive and remember the location
3. Go to the apple menu'->'Control Panels' ->'Appearances'
4. Select the 'Desktop' tab
5. Click on the 'Place Picture' button (located on the right side)
6. Browse to the 'pin800x600.jpg' file you just saved to your hard drive
7. Click the 'Open' button
8. Click the 'Set Desktop' button