Suitable Driver ?

HI
I have to setup PERL to interact with PGSQL.
I have taken the following steps.

1.Installation of perl_5.6.0 under Redhat Linux 7.0
2.Installation of POSTGRESQL under Redhat Linux7.0

Both are working perfectly as seperate modules.

Now I need to interface perl with PGSQL.

I need to what's the best possible soln.

I have installed latest DBI from www.cpan.org

Now i need to install DBD For PGSQL .Is
this the driver i have to work on for pgsql ?.
Or do I have any other option to connect to pgsql
from perl . Indeed i've found out an other way
to use Pg driver provided by PGSQL to interface
perl with pgsql.

I need to exactly know the difference between
use Pg ; and use DBI ; Need to which one is
proceeding towards correct direction under what circumstances.

when I tried to install DBD-Pg-0.93.tar.gz under Linux
i get

Configuring Pg
Remember to actually read the README file !
please set environment variables POSTGRES_INCLUDE and POSTGRES_LIB !

I need to know what these varibles POSTGRES_INCLUDE and POSTGRES_LIB
should point to ...

and when i tried to run perl test.pl, the program to test the
installation of the module which
comes with the tar.
I get the error

OS: linux
install_driver(Pg) failed: Can't locate DBD/Pg.pm in @INC (@INC
contains: /usr/l
ib/perl5/5.6.0/i386-linux /usr/lib/perl5/5.6.0
/usr/lib/perl5/site_perl/5.6.0/i3
86-linux /usr/lib/perl5/site_perl/5.6.0 /usr/lib/perl5/site_perl .)
at (eval 1)
line 3.
Perhaps the DBD::Pg perl module hasn't been fully installed,
or perhaps the capitalisation of 'Pg' isn't right.
Available drivers: ADO, ExampleP, Multiplex, Proxy.
at test.pl line 51

Any body who can clarify is most welcome....

with regards,
Prassanna...