1
Desktop Background:
1920x1200 | 1680x1050 | 1280x800 | 1024x768

Mobile:

iPhone®

BlackBerry®:
320x240 (88xx, 83xx, 87xx series0)
240x260 (81xx(Pearl™), 81xx series)
480x320 (Bold™)
480x360 (Curve™)
360x480 (Storm™ 9530, 9500)

2
Desktop Background:
1920x1200 | 1680x1050 | 1280x800 | 1024x768

Mobile:

iPhone

BlackBerry:
320x240 (88xx, 83xx, 87xx series)
240x260 (81xx(Pearl), 81xx series)
480x320 (Bold)
480x360 (Curve)
360x480 (Storm 9530, 9500)