What I did to setup for the conversion Note I'm doing this on a CentOS 
5.x system
1. Add RpmForge to the YUM repo file
         wget 
http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm 

         rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt
         rpm -K rpmforge-release-0.5.2-2.el5.rf.i386.rpm
         rpm -i rpmforge-release-0.5.2-2.el5.rf.i386.rpm
2. install tesseract
         yum -y install tesseract tesseract-en

This makes it possible to do the following;
         gs -r300x300 -sDEVICE=tiffgray -sOutputFile=ocr_%02d.tif 
-dBATCH -dNOPAUSE <Input.pdf>
     where the options are
             -r is resoultion
             -sDEVICE for monocrome output
             -sOutputFile=outputfilename note %02d causes the page 
number to be inserted into the filename
Followed by
         tesseract inputFile outputfile -l eng
     where the options are
             input is the output tif files from gs
             outputfile will be given a .txt extentsion
             -l language of input file <eng>lish
And then put the pages back together by
             >cat tess-outfile01.txt tess-outfile02.txt ... 
tess-outfilenn.txt > Input.txt

There will some failed conversion/bad guesses by the tesseract program 
so check the final output for correctness.

Bash Script to do the conversion
< This got reformatted and I attempted to put it back the way I 
remembered it.>
< the tesseract step takes a while on each page>
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
#!/bin/bash
# # # # # # Use this script to convert a pdf formated file to text
# The Input file will be split into single page tiff files
# which will be run through tesseract to OCR the files into
# text files. the text files will be reassimbled into a
# single text file.
# # NOTE: There will still be some cleanup of the text files
# as the OCR is not perfect.
# # # # # # # # Get Input file name, and final output filename
InFile=${1:-"infile.pdf"}
TIFFile="${InFile%.pdf}"
OutFile=${2:-"$TIFFile.txt"}
echo "Input from $InFile, OCR output to $OutFile"
if [ ! -e "$InFile" ] ; then
     echo "$InFile not found. exiting"
     exit 1
elsif [ ! -r "$InFile" ]
     echo " Read not allowed on $InFile. exiting"
     exit 1
fi
# setup a temp working area
WrkDir="/tmp/$(date +%s)"
mkdir $WrkDir
echo " Working Dir = $WrkDir"
cp $InFile $WrkDir/
Hdir=$(pwd)
cd $WrkDir
# pwd
gs -r300x300 -sDEVICE=tiffgray -sOutputFile=$TIFFile%02d.tif -dBATCH 
-dNOPAUSE $InFile >files
TifCount=$(grep "Page " files | wc -l)
rm files
#
ls -l *.tif
echo "number of pages to process = $TifCount"
for wtif in $(ls *.tif); do
     wtxt=${wtif%.tif}
     tesseract "$wtif" "$wtxt" -l eng
done
#
ls -l *.txt TxtFiles=$( ls *.txt )
touch $OutFile
for Tf in $TxtFiles; do
#
     echo "Working on $Tf, "
     cat "$Tf" >> $OutFile
done
ls -l
cp $OutFile $Hdir/
cd $Hdir
# once debuged enable the following
rm -fr $WrkDir
exit 0
 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

James C