Heres a great site to pick up some basics
Small Room Acoustics www.rivesaudio.com
Here are some cool and useful things from my teacher John Storyk's website
Fundamental Physics for Acoustics http://www.wsdg.com/resources/resour.php?SL=te&BL=1
RT60 (Reverberation Time) Calculator http://www.wsdg.com/resources/resour.php?SL=te&BL=4
Downloadable .XLS of absorption coefficients from pets to most common building materials to solid concrete :wow: http://www.wsdg.com/resources/resour.php?SL=te&BL=6
Room Mode Calculator .XLS downloadable pre-programmed worksheet with graph http://www.wsdg.com/resources/resour.php?SL=te&BL=5
Please Post any additional cool stuff under this topic.