You can get the source distribution of the current (and other) version of LibRCPS from the links below. Please have a look at the changelog to find out if the newest version includes any improvements relevant to you.

Sun May 30 2010librcps-0.3.tar.gz
Sat Feb 23 2008librcps-0.2.tar.gz
Tue Nov 6 2007librcps-0.1.tar.gz

SVN Repository

If you want to use cutting-edge versions of LibRCPS, which are of course not guaranteed to do anything useful, you can access the source tree with SVN (ignore any issues with the certificate for now):

svn co librcps

You can then later update your copy by entering the directory and issuing a

svn up

Should you have problems using SVN or need a client, please visit the SVN homepage.