To get the latest and greatest AlsaPlayer you will want to check out the CVS tree.
If you have cvs installed on your box you can try the following:
cvs -d:pserver:anonymous@alsaplayer.cvs.sourceforge.net:/cvsroot/alsaplayer login
cvs -z3 -d:pserver:anonymous@alsaplayer.cvs.sourceforge.net:/cvsroot/alsaplayer co -P module_name
where module_name can be alsaplayer (hmmm, this one is mandatory !), fftscope (a nice fft scope vizualisation plugin) or midi (a midi input plugin, use timidity++).
You can also browse the CVS repository. Visit the SourcForge page for all the information regarding CVS.