Download rbinst.zip (tested on Mini, Nano and 5G iPod 30GB)
 

This installer has several features:
 

• Your document is safe:   This installer does not remove your data. All the music, files and settings are automatically taken over.
• Easy to use: As is shown below I deleted options as much as possible. AppleOS is automatically selected as the default OS.
• Quick installation: It takes only 30 seconds or so to complete installation.
• Supports many types of iPod  (iPod 1G, 2G and 3G is not supported)
• iPodLinux is installed as well as Rockbox.  If you do not need iPodLinux, use this

Usage:
 

1. Download rbinst.zip.
   Extract the rbinst.zip.
   There are only two files. rbinst.exe (installer) and readme.html (document).
   Run rbinst.exe.

2. Installation starts automatically.
If a message "iPod is not found" comes out, make sure that your iPod is connected. Sometimes it would be a good idea to restore your iPod with iPod updater.

3. Wait a while. If "Now Installing" blinks, installation is working fine.
  Installing might take a few minutes if your PC does not support USB2. Be patient and just wait.

4. Success. Disconnect your iPod and choose "Rockbox" from the boot menu.