I enjoy downloading music to my computer and portable digital music player. In fact, I cannot remember the last time I was at a music retailer. I’m a convert. I prefer listening to music samples on the Internet and buying only the songs that I want and not wanting to buy an entire disc where I may like only a few song tracks. This is the reason why iPods from Apple Computer Inc. (AAPL) have grown exponentially in popularity to the current cult status. A friend of mine received a 30GB iPod for Christmas and trust me you have never seen someone so excited.A 30GB iPod can hold up to 7,500 CD quality songs. That is impressive. Apple is a trendsetter in my estimation. From its MAC to the iPod, CEO Steve Jobs has a keen knack for trends. These portable music devices have so much memory because he probably expects a massive shift to CD burning and downloadable music. Apple’s iTunes Music Store is booming.Just last week, the International Federation of the Phonographic Industry released its research into the digital music industry and the results were not a surprise. Just like how online DVD movies have dominated the video rental market, dominated by Netflix Inc. (NFLX), and pushing incumbent Blockbuster Inc. (BBI) to the sidelines, the exponential growth of the online music business has been on an explosive upward path.According to the research, sales of digital music globally increased by over 300% in 2005 to $1.1 billion. The research said digital music accounts for about 6% of total music sales, up from very little two years back.The competition in the industry is fierce and expected to ramp up going forward. This could lead to consolidation in the industry down the road and result in lower prices. We could see the bigger and more established players taking out the smaller up and comers.Besides Apple, there are a slew of online music sites. Probably the most well known is Napster Inc. (NAPS). Napster reported it has over 500,000 subscribers but has yet to turn a profit and is not expected for the time being. But the company has minimal debt and a whopping $128 million or $2.91 per share in cash. Given that the current share price is 3.08, this implies you are paying a mere $0.17 for the company’s asset and potential. This is pretty good and enticing for speculators, but then Napster must deliver profits. Napster could be the dark horse in the digital music business.In addition to Apple and Napster, there is also the growing Rhapsody music service from RealNetworks Inc. (RNWK) and Yahoo Music from Yahoo Inc. (YHOO).Other providers include puretracks.com, MSN Music, AOL Music Now and Musicmatch. You can even download music at $0.88 per track from Wal-Mart Stores Inc. (WMT).Long lives digital music.