my $receiver = Mail::Transport::POP3->new(...); my $message = $receiver->receive($id);
See SYNOPSIS in Mail::Transport
Each object which extends Mail::Transport::Receive implement a protocol which can get messages into your application. The internals of each implementation can differ quite a lot, so have a look at each separate manual page as well.
Current message receivers:
Implements the POP3 protocol. See also Mail::Box::POP3.
See DESCRIPTION in Mail::Transport