Not sure if this has been referenced elsewhere, but I found an interesting article which does an excellent job of explaining Speed and Feed for our class of CNC Router.
There are also links to a basic spreadsheet to calculate feed. (I would have attached but cannot upload .xls) With my limited knowledge of this topic the spreadsheet appears to fit better than others I have seen. Just started experimenting with the info generated but the feeds calculated seem to make my cuts much quieter.
I hope this helps someone struggling with this area, like me.