This is a very quick explanatory video which hopefully explains how a DSSS signal (as used by all of today's 2.4GHz radio control systems such as Spektrum DSM2 and DSMX, Futaba Fast, Hitec AFHSS etc) allows more multiple systems to share exactly the same part of the band without interfering with each other.
The PN (pseudo-noise) codes effectively "scatter" the signal across the channel being used by the DSSS signal so that the chances of another signal affecting it are very remote.
This could be seen as a kind of "micro-hopping" within the DSSS signal itself -- although it shouldn't be confused with the much larger jumps that today's "hopping" systems use to move the entire DSSS signal around the band at random.
If you have any questions, please feel free to ask and I'll do my best to explain.