No subject

 	echo test | mail -s test thomas.perron at gmail.com

If that doesn't work and you don't get any useful clues from the command 
output, start digging where your syslogd logs messages.

Next, from a shell command line, try

 	echo test | mail -s test 5555551212 at txt.att.net

Note that this recipient is specific to this carrier.

If that works, it should work in Asterisk assuming you don't have any path 
or permissions issues.

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                              Fax: +1-760-731-3000