iPod Touch 3G – iPod3,1_5.0.1_9A405_Restore.ipsw
iPod Touch 4G – iPod4,1_5.0.1_9A405_Restore.ipsw

iPad 3G/WiFi – iPad1,1_5.0.1_9A405_Restore.ipsw
iPad 2 WiFi – iPad2,1_5.0.1_9A405_Restore.ipsw
iPad 2 GSM – iPad2,2_5.0.1_9A405_Restore.ipsw
iPad 2 CDMA – iPad2,3_5.0.1_9A405_Restore.ipsw

iPhone 3GS – iPhone2,1_5.0.1_9A405_Restore.ipsw
iPhone 4 – iPhone3,1_5.0.1_9A405_Restore.ipsw
iPhone 4 CDMA – iPhone3,3_5.0.1_9A405_Restore.ipsw
iPhone 4S – iPhone4,1_5.0.1_9A405_Restore.ipsw

Apple TV 2G – AppleTV2,1_4.4.3_9A405l_Restore.ipsw

I’m a little late with these 5.0.1 links, what with Apple providing it as a delta OTA update. Updating right on the phone is a much smaller download and doesn’t require iTunes at all, so that’s probably the easier way to do it, but these links still may be handy in some situations.