Well when I fixed all of the bugs in this plugin I thought that now there is nothing left to do with this plugin
But when I walked out of the office I thought it would be good to add some more options
So let me explain to you what the future options be(As soon as I find some free time :D)
1- type of the extra field(number, string(min, max length), combo box, check box)
2- string validation(with regular expression)
3- show the extra fields in the post or not
4- send the extra fields to the email(along with the main fields)

These are what I thought until now
If you have anymore suggestion please tell me and I will add it here and of course I will mention your name in the code(with a link);)
This post will be a future reference for me to remember what I wanted to do with this plugin
p.s: If you make any improvement for the plugin send it to me in order not to lose the improvements when I update the plugin to a newer version
Wish me free time:P