* Amazon tumbles, Microsoft climbs after earnings
* New home sales data due
* Futures off: Dow 35 pts, S&P 6.5 pts, Nasdaq 14.75 pts
By Chuck Mikolajczak
NEW YORK, Oct 24 (Reuters) - U.S. stock index futures dipped on Friday, putting the S&P 500 on track to trim its weekly gain, following disappointing results from Amazon and as the first diagnosed case of Ebola in New York City raised concerns about the spread of the virus.
* Amazon plunged 10.9 percent to $279.15 in premarket trade after the online retailer's sales projections for the crucial holiday quarter disappointed Wall Street and third-quarter results missed forecasts.
* Microsoft, up 2.7 percent at $46.25 before the opening bell, may help curb declines after it reported higher-than-expected quarterly revenue, while keeping its profit margins largely intact.
* Procter & Gamble edged up 0.1 percent to $83.30 in premarket after the world's largest household products maker posted quarterly results and said it would split its Duracell battery business into a separate company.
* The S&P 500 is up 3.4 percent for the week, putting the index on pace for its first weekly gain in five, powered largely by solid corporate earnings reports. The benchmark index is down 3 percent from its record high on Sept. 18.
* Concerns over the spread of Ebola continued to vex the market. A doctor who worked in West Africa with Ebola patients was in an isolation unit in New York City on Friday after testing positive for the virus, becoming the fourth person diagnosed with the disease in the United States and the first in its largest city.
* Ford Motor Co's third-quarter earnings beat Wall Street expectations on a strong showing in North America and China. Shares of the automaker climbed 0.6 percent to $14.48 in premarket trade.
* New home sales data for September is due at 10:00 a.m. (1400 GMT). Expectations call for a seasonally adjusted annual rate of 470,000 units, down from the 504,000 in the prior month.
* European shares pared early losses on Friday as investors bet the fallout for the banking sector from stress test results due on Sunday should be contained, and took a more measured view of New York's first case of Ebola.
* In Asia, MSCI's broadest index of Asia-Pacific shares outside Japan slipped 0.1 percent, though Japan's Nikkei share average bucked the trend rising 1.0 percent, led by gains in drug companies.
Futures snapshot at 7:32 a.m. (1132 GMT):
* S&P 500 e-minis were down 6.5 points, or 0.33 percent, with 215,902 contracts changing hands.
* Nasdaq 100 e-minis were down 14.75 points, or 0.37 percent, in volume of 34,456 contracts.
* Dow e-minis were down 35 points, or 0.21 percent, with 37,016 contracts changing hands. (Editing by Bernadette Baum)