There is some guide for IRAF installation on 64bit platform - there: http://mjhutchinson.com/journal/2006/11/05/install_iraf_on_ubuntu_edgy_amd64.

Bellow are script which you should run under either root account or iraf account to get IRAF installed on 64bit Ubuntu. Most probably you will like to place them under /iraf directory and run them from there.

First, run following script under root:

apt-get install tcsh
 
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/t/termcap-compat/termcap-compat_1.2.3_i386.deb http://old-releases.ubuntu.com/ubuntu/pool/universe/libc/libc/libc5_5.4.46-15_i386.deb http://old-releases.ubuntu.com/ubuntu/pool/universe/l/ld.so/ldso_1.9.11-15_i386.deb http://old-releases.ubuntu.com/ubuntu/pool/universe/n/ncurses4.2/libncurses4_4.2-10_i386.deb
 
dpkg -i --force-architecture ldso_1.9.11-15_i386.deb
dpkg -i --force-architecture libc5_5.4.46-15_i386.deb
dpkg -i --force-architecture termcap-compat_1.2.3_i386.deb
dpkg -i --force-architecture libncurses4_4.2-10_i386.deb
 
apt-get install ia32-libs ia32-libs-gtk linux32
 
addgroup iraf
adduser --home /iraf/iraf/local --shell /bin/tcsh --ingroup iraf iraf
 
chown -R iraf:iraf /iraf

Then, su to iraf:

root@host:/iraf# su iraf
iraf@host%

and run following as iraf user:

#!/bin/tcsh
mkdir /iraf/iraf
mkdir /iraf/iraf/local
mkdir /iraf/irafbin
mkdir /iraf/irafbin/bin.linux
mkdir /iraf/irafbin/noao.bin.linux
mkdir /iraf/x11iraf
mkdir /iraf/extern
 
#download and extract the source
cd /iraf/iraf
wget http://iraf.net/ftp/iraf/V2.13-BETA/as.pcix.gen.gz
tar -zxf as.pcix.gen.gz
rm as.pcix.gen.gz
 
#download and extract the redhat IRAF binaries
cd /iraf/irafbin/bin.linux
wget http://iraf.net/ftp/iraf/V2.13-BETA/ib.rhux.x86.gz
tar -zxpf ib.rhux.x86.gz
rm ib.rhux.x86.gz
 
#download and extract the redhat NOAO binaries
cd /iraf/irafbin/noao.bin.linux
wget http://iraf.net/ftp/iraf/V2.13-BETA/nb.rhux.x86.gz
tar -zxpf nb.rhux.x86.gz
rm nb.rhux.x86.gz
 
#move the redhat binaries to the linux directory
cd /iraf/iraf/unix/bin.redhat/
mv * ../bin.linux/
 
 
setenv iraf /iraf/iraf/
cd $iraf/unix/hlib
source irafuser.csh
 
./install -n
 
echo When ./install -n in the $iraf/unix/hlib runs well, you may
echo run ./install (without -n) as root to finish installation.

After this, exit su from iraf, and run iraf/unix/hlib/install:

root@host:/iraf# ./iraf/unix/hlib/install