[vjsreevs]

1) How do I read a file into an array?

using the explode command
(or)
using $myarray = file("/path/to/somefile"); where $myarray is an array. each line in the file, is now a cell in the array

[vjsreevs]

2) What is sizeof in multi-dimensional arrays
will tell you how many elements r there in that particular dimension

[vjsreevs]

3) How can I get the size of an IMAP message?

You can retrieve the total size of the message with:

$size = $mailsize->bytes;
where

$mbox is a pointer to the inbox and $x is the message number:

$mailsize = imap_fetchstructure($mbox, $x);

[vjsreevs]

4) what is Mailing list software

Mailing list software - the order of mailing combines mails to the same domain and delivers them in a row to the same mailserver.

[vjsreevs]

5)How can I use an external mail server from PHP?

exec sendmail
(or)
use one of the many PHP SMTP implementions that open an actual socket
connection to the remote mail server