Updated from 1:18 p.m. EDT with new stock prices

Apple's ( AAPL) strong earnings boosted the tech sector Tuesday, despite mixed results from several other big names.

Aided by strong sales of Mac computers, iPods and iPhones, Apple blew away Wall Street's third-quarter expectations late Monday, soaring to an all-time high before pulling back slightly. The company posted net income of $904 million, or $1.01 a share, vs. $546 million, or 62 cents a share, in the year-ago period. Analysts polled by Thomson Financial had forecast earnings of 86 cents a share. Revenue of $6.22 billion also topped the consensus of $6.07 billion. Shares rose $11.80, or 6.77%, to $186.16.

Millicom International Cellular ( MICC) also was trading above its 52-week high. Shares gained 21.32% after beating analysts' expectations for the third quarter. Excluding discontinued operations, the Swedish telecommunications company reported revenue of $686 million, vs. $388 million in the year-ago period. Analysts were expecting revenue of $663.9 million. The growth was driven by a 77% increase in its subscriber base, bringing it to 20 million. Shares were up $18.49 to $105.20.

Level 3 Communications ( LVLT), however, was plummeting 24.07% after cutting its cash-flow outlook for the next two years. The company said it failed to keep up with network upgrade expenses as customers used its services more. As a result, the company lowered its full-year consolidated adjusted earnings before interest, taxes, depreciation and amortization to between $813 million and $833 million from previous guidance of $860 million to $920 million. In 2008, the company sees EBITA falling between $950 million to $1.1 billion from its earlier forecast of $1.15 billion to $1.3 billion. Shares were falling $1.04 to $3.28.

Apple, Millicom and Level 3 are all components of the Nasdaq 100, which was gaining 47.73 points to 2,205.18.

Shares of Art Technology Group ( ARTG) jumped 19.35% after the e-commerce software maker posted a wider third-quarter loss but guided higher for the full year. The company sees 2007 revenue of between $130 million and $133 million, above analysts' expectations of $128.1 million. Shares gained 66 cents to $4.07.

Zoran ( ZRAN) also spiked 15.05% after the chipmaker beat third-quarter expectations. The company reported earnings of 26 cents a share on $146.4 million in sales, vs. analysts' forecast of earnings of 39 cents a share on revenue of $138.5 million. CIBC World Markets upgraded the stock to sector outperform from sector perform, while Needham upped it to buy from hold. Shares were gaining $3.14 to $24.00.

On the losing side, Texas Instruments ( TXN) shares were dropping 8.29%, after the chipmaker offered disappointing fourth-quarter guidance. The company sees revenue of between $3.4 billion and $3.68 billion, which is below the consensus forecast of $3.71 billion. While the company beat expectations for the third quarter, shares were falling $2.84 to $31.43.

Lexmark ( LXK) shares were dipped 7.18% after the printer maker posted declining third-quarter revenue and profits and announced plans to cut 1,650 jobs. Shares were losing $3.14 to $40.60.

Unisys ( UIS) shares shed 17.83%, after the tech consultant posted a narrowed third-quarter loss that underwhelmed Wall Street. The company reported a net loss of $31 million, or 9 cents a share, vs. $77.5 million, or 23 cents a share, in the year-ago period. Revenue slipped to $1.39 billion, from $1.41 billion. Analysts expected a profit of 4 cents a share on revenue of $1.40 billion. Shares were losing $1.33 to $6.13.