[LAU] mixing techniques and synth : book references ?

Hi everyone, I've been try to compose for several months/years now and i'm never pleased with the mix and with the synth sounds. My use of effects and filters are more or less random. I'm self-educated here but not very well ;-). More, each time I listen to my tracks on a new system, it sounds different. So I'm willing to learn some mixing techniques (and some synth techniques as well). I'd like to have a better understanding of sound mixing and synth. A little studying will do me good. Do you know any good book references about these subjects, french or english ? Of course if they tackle the subject of free audio software as well I would just be great. Thanks for your help ! jy