I'm trying to be unassuming here but judging from your question you don't understand how cvs works.
To download (or rather check-out your working copy of) the latest version of acs-pg execute after your login:
cvs -d:pserver:anonymous@cvs.acs-pg.sourceforge.net:/cvsroot/acs-pg co acs-pg
For the rest of the story read some cvs documentation (eg.
http://cvsbook.red-bean.com/ ).