CPAN represents the development interests of a cross-section of the Perl community. It contains Perl utilities, modules, documentation, and (of course) the Perl distribution itself. CPAN was created by Jarkko Hietaniemi and Andreas König.

The home for CPAN is http://www.cpan.org/, but CPAN is also mirrored on many other sites around the globe. This ensures that anyone with an Internet connection can have reliable access to CPAN's contents at any time. Since the structure of all CPAN sites is the same, a user searching for the current version of Perl can be sure that the stable.tar.gz file is the same on every site.

If you want to use anonymous FTP, the following machines should have the Perl source code plus a copy of the CPAN mirror list:

ftp.perl.com

ftp.cs.colorado.edu

ftp.cise.ufl.edu

ftp.funet.fi

ftp.cs.ruu.nl

The location of the top directory of the CPAN mirror differs on these machines, so look around once you get there. It's often something like /pub/perl/CPAN.

bioperlI personally like to use ActivePerl for it's nice installations. The ActivePerl can be downloaded for free at
      
       http://www.activestate.com/

although you have to register to do so. The site also have many other goodies but you might have to pay for it.
As a  biologist you might want to use bioperl, which is specially designed for biologists for quick learning and with many bioinformatics related modules the are ready to use such that it saves you lots of times to reinvent the wheel.
There is a very nice online tutoral for bioperl scripting and you should learn it if you just want to focus on sequence manipulation, accessing of databases such as swissport, genbank, genpept, embl etc.
You can easly parse the results of various molecular biology programs including Blast, clustalw, etc by bioperl so that one can analyze large quantities of sequence data at easy.