It's like a simple form really. Nothing different than a traditional form which sends data to a certain e-mail. You can program one in PHP yourself, it's not difficult at all
not diffucult, it depends if you want an admin area like you say.. stored so you can look later on... so you need a delet from data option, than you need a user / probably a registration... the list goes on.
if you are using zymic host... email function is disabled. so you actualy can't send emails :/ so i guess there is the database type thing...