ganjlePM handles all $_REQUEST parameteres. That means that you can send/receive/delete messages by POST or GET. Below you can find the parameters for each action:

Send message: action=send, text=whatever, ID=whatever

Read messages: action=read, key=yourkey
(the message count is inside a div of that belongs to the class notifierdata and message text along with size/date/delete_link are inside divs that belongs to the class message)

Empty inbox: action=empty, key=yourkey

Delete message: action=delete, key=yourkey, messagedate=whatever
(messagedate should be exactly what is printed as date when you read the message)