How to send mails from Sharepoint Custom List ?

Hi ,

I have one sharepoint list that takes feedback from the users. Now we already have the column "created by"; what we want is if some user creates a new feednback or in other words a new list item we want a particular user x to have to reply back to that person (in the column created by or in the other words the user that created that item). How can we achieve that.

For further info the llist is a part of portal where in only that list has contribute access for the users and rest of them have read access.

Can anyone help asap.

Thanks