Even if Sofmea will help you measure and optimize your speaker, here are some other tools which may interest you :
Audacity : Free audio editor and recorder. The best tool to record output signal from your speaker before using the "WAV" files inside Sofmea.
WinISD : Free speaker designing software for boxes. You can design Closed, Vented and Bandpass boxes, usefull befor using Sofmea to design the cabinet.
Gnuplot : usefull tool to better visualize frequency responses measured with Sofmea or waterfall diagramm.
Arta : Another audio measuring software. Output files (.frd) can be used to compute the frequency response of a box for a special crossover.

Great web directories :
Directory Audio
Webotopia B2B Directory
Premier directory

Try to design your own "Do It Yourself" loudspeakers