Apple has released the next version of its groundbreaking online music store, and it is quite an upgrade. While the interface remains the same (if it ain't broke...), the new features are likely to keep iTunes well ahead of the competition.

• iMix - Previously, iTunes had provided playlists selected by famous musicians in an effort to introduce users to music or just to let fans see what their favorite artists were listening to. With iMix, anyone can upload their personal playlist for other users to view, download, and rate.
  
• Party Shuffle - An enhanced random feature, this automatic playlist generator allows you to mix up your songs into a steady stream of music that you can add to and delete from on the fly.
  
• Apple Lossless - A new encoder that retains the same CD sound quality as Apple's traditional AAC format but at half the size. Essentially, if you were to convert all of your files to this format, you would double the available space on your iPod or hard drive.
  
• WMA Conversion - A sorely needed feature for Windows users who have half of their music collection in AAC and the other half in WMA. Now, iTunes users can convert from Microsoft's proprietary format into Apple's, making their entire song list accessible to iTunes.
  
• Radio Charts - Perfect for anytime you're trying to figure out just what that song was you heard on the radio. These charts contain playlists from 1,000+ radio stations, searchable by genre and geography.
  
• Printing - iTunes now allows you to print jewel case inserts and linear notes. A particularly cool feature is the automatic mosaic you can create of the various album covers for songs included on the CD.
  
• Music Videos & Movie Trailers - While previously accessible on Apple's web site and elsewhere, videos and trailers are now integrated into the iTunes engine through QuickTime. While you can't download them, they are free to watch via streaming video.
  
• Free Music - Each week, iTunes will release one song by a popular artists as a free download.
  

On top of these new features, iTunes now has a library of more than 700,000 songs, making the service the industry leader in digital music delivery. Combined with the seamless integration of Apple's iPod, iTunes 4.5 leaves the competition in the dust.