If you get a No Database Drivers available! error when trying to install SQL-ledger, it is most likely because you haven't installed the perl/postgresql drivers. With FC3 you can install them through:
yum install perl-DBD-Pg
These weren't the only difficulties I encountered with the sql-ledger installation process, so I have detailed the steps I took here:
yum install postgresql postgresql-server php-pgsql postgresql-pl perl-DBD-Pg
Then download and run the sql-ledger setup script
mkdir /usr/local/sql-ledger
cd /usr/local/sql-ledger
wget http://www.sql-ledger.org/source/setup.perl
chmod +x setup.perl
./setup.perl
Follow the on-screen prompts, and then once that has completed you will have to setup the database user etc..
su postgres
createuser sql-ledger
createdb sql-ledger
createlang plpgsql template1
You will then probably need to change the security settings of postgresql to trust local users, I did this by editing pg_hba.conf and changing the authentication to
local all all trust
Finally you should visit the http://localhost/sql-ledger/admin.pl script in your webbrowser to complete the setup.