I am currently building a "social" website where people can send messages to eachother.
When they are on their profile page they have this menu, one of the items are "Inbox".
This is where the user can send personal messages to other users by typing the other users name, write the messsage and click send.

Now, what i am wondering is, where would i start?
Should the messages be stored in a database? In a txt file?
How do i send to users and knowing who the message is from?

You get the idea, i just need a little kick to get started on this.

Thx in advance!