Janine, you don't have to register with sourceforge if all you need to do is a checkout. All you need is a cvs client and those two commands:
cvs -d:pserver:anonymous@cvs.acs-pg.sourceforge.net:/cvsroot/acs-pg login
Cvs wants you to provide a password at this point but since password is empty (for all sf projects) just press enter here.
cvs -z3 -d:pserver:anonymous@cvs.acs-pg.sourceforge.net:/cvsroot/acs-pg co acs3-pg
You only need to register if you want to commit changes to a repository (either of your own project or someone else's project if they've given you permissions).
