RdbiPgSQL - problem to install it

hi,
i have a problem to install RdbiPgSQL
on  osx 10.4.6 + R-2.2.1
i've insatlled pgsql + postgis (binary version)
in /usr/local/pgsql

but when i try to install it ....

* Installing *source* package 'RdbiPgSQL' ...
creating cache ./config.cache
checking for PQconnectdb in -lpq... no

The downloaded packages are in
	/private/tmp/Rtmp19BJ6U/downloaded_packages

I could not find your PostgreSQL client libraries!
Use --with-pgsql-libraries=PATH; if running R's INSTALL,
use --configure-args='--with-pgsql-libraries=PATH'; or
set PG_LIB_DIR in your environment to the library path,
and rerun the configure/install.

ERROR: configuration failed for package 'RdbiPgSQL'
** Removing '/Library/Frameworks/R.framework/Versions/2.2/Resources/ 
library/RdbiPgSQL'

how can i install it ?
have you any suggestions ?
thanks!