What happens to people who have never heard about Jesus? There seems to be general consensus inside Christianity that in order to be saved, you must have faith, and that this faith has to be in Jesus Christ. Here is one verse sometimes cited for the necessity of having faith:


  Hebrews 11:6 (ESV)
  And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him.


There is also another verse that seems to indicate that this faith only comes from hearing specifically about Jesus Christ:


  Romans 10:17 (ESV)
  So faith comes from hearing, and hearing through the word of Christ.


Isn't this kind of rough luck on your average illiterate jungle tribe without contact with the outside world? How is it fair of God to offer salvation only to a limited subset of people who happen to have access to this news? Are they to be dammed for something out of their control?
At the heart of this question (and many similar ones) is another question: Is God fair?

If God requires acknowledgments of truths that people haven't had a chance to hear in order to be saved, then of course He is not fair.

If we begin with the assumption that God will never act unjustly or unfairly though, then we can assume that He will make Divine provision for everyone, including tribes in remote jungles, to respond to Christ. This provision does not need to be a human delivering a message, but can be angels, dreams, visions, or other unknown methods.

Look at the following quote from Jesus:


  Joh 5:24-25 NIV  "I tell you the truth, whoever hears my word and
  believes him who sent     me has eternal life and will not be
  condemned; he has crossed over from death to life. (25)  I tell you
  the truth, a time is coming and has now come when the dead will hear
  the voice of the Son of God and those who hear will live.


What is meant by "the dead will hear the voice of the Son of God" can be understood different ways, but I think one of the ways we may possibly understand it is those who have died without the opportunity of receiving Christ will have that opportunity.

However God offers this choice to people, if you assume He is good and will always act justly, whatever He needs to do to accomplish this (He is God after all) He will do. Believing in God's essential goodness is in itself a mark of faith (as you quoted in your question):


  Heb 11:6 NIV  And without faith it is impossible to please God,
  because anyone who comes to him must believe that he exists and that
  he rewards those who earnestly seek him.