I'm looking for a command line like cleancode's email program which would allow me to send emails from the command line without setting an MTA (and would allow me to use separate accounts for each users, without touching the MTA's configuration).
Is there a PPA with cleancode's email program? Is there other similar program which is packaged with ubuntu?
Would msmtp fit your needs? It means you can run SMTP commands locally without running a full SMTP server. msmtp will just forward it to a SMTP server and is configured by a file in your home directory, so different users can have different configurations.
msmtp has been in the ubuntu repositories for a few years now.
So you want an MTA, without setting up an MTA?
I use an ssh tip http://dabase.com/e/01087 when I'm in a hurry and it gets around firewalls that block outgoing mail.