SSH-Autoloader.sh

#!/bin/bash
for f in `find ~/.ssh -perm 600 -type f`
do
  add_key=true
  for k in `ssh-add -l`
  do
    if [[ "$k" = "$f" ]]
    then
      add_key=false
    fi
  done
  if [ $add_key = true ]
  then
    `ssh-add $f`
  fi
done

Could be cleaned up a bit to be more efficient, but it works! You can add this to your .bash_profile or .zshrc to autoload all your SSH keys.