NEW YORK ( TheStreet) -- Apple ( AAPL) dropped 4.8% to $331.71 in pre-market trading Tuesday, after the company announced that CEO Steve Jobs would take a medical leave of absence for an unspecified amount of time. Chief Operating Officer Tim Cook will be responsible for the company's day-to-day operations. Apple plans to report earnings after the bell Tuesday, which TheStreet will live blog. Nokia ( NOK) fell 1.7% to $10.80, as it said it will discontinue free music downloads with its handsets in most markets. The world's largest cellphone-maker had launched the Ovi Music Unlimited as a competitor to Apple's iTunes. IBM ( IBM) was down 0.35% to $149.48, as the company prepares for its fourth-quarter earnings announcement Tuesday afternoon. Analysts expect IBM to generate adjusted profit of $4.08 per share on revenue of $28.26 billion. The mobile app market will be worth $25 billion by 2015, up from $6.8 billion in 2010, according to a new market research report by MarketsandMarkets. Apple's App Store is expected to hold a 20% share of this market, according to the report. Cheezburger Network, which runs well-known blogs like ICanHasCheezburger and FAILBlog, has raised $30 million in its first round of venture funding led by Foundry Group. The Cheezburger Network has 16.5 million unique monthly visitors, and 375 million monthly page views. --Written by Olivia Oran in New York. >To follow the writer on Twitter, go to http://twitter.com/Ozoran. >To submit a news tip, send an email to: email@example.com.