The Pegasus prebuild tarballs can be downloaded from the Pegasus Download Page.
Use these tarballs if you already have HTCondor installed or prefer to keep the HTCondor installation separate from the Pegasus installation.
Untar the tarball
# tar zxf pegasus-*.tar.gz
include the Pegasus bin directory in your PATH
# export PATH=/path/to/pegasus-install/bin:$PATH