It turns out the best tool for synching music to your Windows Phone 8 handset is Windows Media Player, which can at least auto-generate playlists.
What about those playlists you worked hard on over the last two yours with your Windows Phone 7.5 handset however, which is not compatible?
It turns out simply renaming the extension from .ZPL to .WPL will make them compatible with Windows Media Player, allowing the app to sync the playlist to your Windows Phone 8 phone.
To find the Zune playlists, search for .ZPL,Â (they are usually under C:\Users\XXXXX\Music\Playlists, where XXXXX is your account name on your PC), rename the extension to .WPL, launch Windows Media Player, connect your phone and drag the newly detected playlist to your sync tab (above).
The Windows Phone 8 Sync app and Xbox Music both are still very poor replacements for the Zune apps, but hopefully this tip will help ease the pain somewhat.