You can also try the one-click installers at EnterpriseDB.
The PostgreSQL installers include the database server, pgAdmin and
StackBuilder. The 8.x installers are supported on Ubuntu 6.06 and
above, Fedora 6 and above, openSUSE 10 and above, SLES 9 and above,
CentOS/RHEL 4 and above, Mac OS X 10.4 and above (Intel and PPC), and
Windows XP and above. The 9.x installers are supported on Ubuntu 8.04
and above, Fedora 10 and above, openSUSE 11 and above, SLES 11 and
above, CentOS/RHEL 5 and above, Mac OS X 10.5 and above (Intel 32 and
64 bit), and Windows XP and above.
After installing, you can then use the StackBuilder to add PostGIS. It should include the shp2pgsql-gui with pgadmin3.
Alternate answer:
pkgs.org lists shp2pgsql-gui as part of the postgis-1.5.3-1.el6.x86_64.rpm package. You could try replacing your current PostGIS with it. Once you've removed your old PostGIS, you can install the new one by following these steps:
Download the latest epel-release rpm from
http://download.fedora.redhat.com/pub/epel/6/x86_64/
Install epel-release rpm:
# rpm -Uvh epel-release*rpm
Install postgis rpm package:
# yum install postgis
After installation, check to see if shp2pgsql-gui exists. If yes, add the following to your pgadmin3's plugins.ini file under /usr/share/pgadmin3/:
;
; pgShapeLoader (Linux):
;
Title=PostGIS Shapefile and DBF loader
Command=$$PGBINDIR/shp2pgsql-gui -U $$USERNAME -d $$DATABASE -p $$PORT -h $$HOSTNAME
Description=Open a PostGIS ESRI Shapefile or Plain dbf loader console to the current database.
KeyFile=$$PGBINDIR/shp2pgsql-gui
Platform=unix
ServerType=postgresql
Database=Yes
SetPassword=No