http://tldp.org/LDP/abs/html/ should be useful to you. Edit: specifically,
this should help. To get the filenames into variables, I'd use awk. Let's say you've read a line of the file into the variable "line". Then, you can use the following to get the old and new filenames into variables "oldname" and "newname" respectively:
oldname=`echo $line | awk '{print $1}'`
newname=`echo $line | awk '{print $2}'`
You can then just use these variables with mv to rename the files, e.g.
mv $oldname $newname.
HTH.