You can fetch the Template Toolkit from any CPAN site. It can be found at the following URL: http://www.cpan.org/modules/by-module/Template/.

Once you've unzipped and untarred the distribution, installation proceeds via the usual route. For example:

panic% perl Makefile.PL
panic% make
panic% make test
panic% su
panic# make install

Alternately, you can use the CPAN.pm module to install it. Full details on installation can be found in the INSTALL file in the distribution directory. There is also a README file that is worth at least a passing glance.