local smtp agent

[ke han]

I have an application on my FreeBSD 6.1 server which needs to send  
out e-mail.  I have access to a a well managed SMTP server on another  
server.  I would like to send e-mail from my app to a local SMTP  
agent which then handles sending to the "real" SMTP server in a more  
fault-tolerant manner than I can easily achieve with my app code.
I believe this to be a typical scenario.  What is the recommended  
approach?  Use the default sendmail?or use procmail?  Is there a  
howto someone can point me to?  Does the recommendation change if the  
local SMTP agent needs to connect to the "real" SMTP server using TLS  
with id and password?
thanks, ke han