I just find a step by step guide on how to play FLAC on iPod in lossless or lossy way at How to Play FLAC on iPod in Lossless or Lossy Way?

This guide applies to:

    * Convert FLAC to Apple Lossless or AIFF to play lossless FLAC on iPod Touch, iPod Shuffle, iPod Nano, iPod Classic, iPod Mini, iPhone 3G, iPhone 3GS, iPhone 4, iPad, iPad2, iTunes, Quicktime, iMovie, FCP, FCE.

    * Convert FLAC to MP3 to play FLAC on iPhone/iPad/iTunes/iPod/Quicktime/iMovie/FCP/FCE/Windows Media Player in lossy way.

    * Convert FLAC to other audio formats including lossy AC3, AU, M4A, MP2, OGG, RA, and WMA.