Spotify is compatible with all the iPod classic models, as well as the iPod shuffle and iPod nano. Any iPod that connects via a USB cable connection, rather than the very first model that required a FireWire connection (isn’t there a museum you can donate that to?), will work.
To sync music from Spotify to your iPod, follow these steps:
You can’t sync if you have both of these applications open because it could cause conflicts.
Your iPod should appear below Devices in your Spotify window’s left sidebar.
The first time you connect your iPod to Spotify, you’ll be asked if you want to erase your iPod and sync it with Spotify. In subsequent syncs, you aren’t asked to do this again as long as you continue using Spotify for your syncs.