So I guess this would be the final solution ?

for file in $(find . -name '*' -type f -print ) ; do
sed 's/mysite.com/mysite.net/g' $FileName > $$TempFile
mv $$TempFile $FileName
done

If i want to run this command do I type this out on the command line or do i have to make a shell script and run the shell script ?