Ok, in order ...
First, there are a couple of oddities with the Pentatonic scale when it comes to matching up chords.
The first one stems from the fact that the Minor Pentatonic can also be thought of as a Minor scale with missing notes, and when working with chord we would tend to go back to the minor scale rather than use the pentatonic sincs it is technically quite difficult to make nice chords just out of the pentatonic scale. Since the Minor Penta is a subset of minor, it will work ok over chords made up fgrom notes in the minor scale.
Secondly, it is usually a nono to mix minor and major 3rds, however, when playing minor pentatonic this rule is suspended and you get the blues

So with this in mind, I will answer your questions a little more loosely or we will run into trouble!
QUOTE (Twibeard @ Oct 26 2007, 12:54 PM)

1. If I play a C minor pentatonic scale, will all the "C chords" be found inside that scale ?
Not quite sure what you meant here, but if for instance you pick a scal, lets say C major, there is a list of chord cariations that work for that scale. In the case of C major you could use C, Dm, Em F, G, Am Bdiminished - these are chords that are made up from notes out of the scale, and there is a theory lesson on it
here.
QUOTE (Twibeard @ Oct 26 2007, 12:54 PM)

2. Also I wonder about the backing tracks, say the backing track is made entirely of chords, and I play the C minor pent. scale, what are the rules, chord-wise, for that backing track?
The rule (and it is more of a guideline) would be ti use chords derived from the scale (as in the lesson above). In the case of C Minor Pentatonic you could use chords from the C Major Scale - the ones I listed above.
QUOTE (Twibeard @ Oct 26 2007, 12:54 PM)

3. Last question, If I play the C minor pent scale in a song, dose the entire song have to be in that scale then?
Not at all! Three things here:
1. Chords and Scales interact - as longa s they align you can change between different scales. For instance, over a chord of C minor, you could play C Pentatonic, C Phyrgian, C Dorian ... there is a long list.
2. Even given the above, you can slide in notes or even parts of scales that conflict as long as you do it in passing - this is called playing outside (as in outside the scale)
3. Finally, Keys are not the same as scales, and you can change keys all the time in a song of you want to, its called Modulation, and generally includes a change of chord sequence )though not every change of chord sequence is necessarily a modulation).