Hosted SMTP Server Recommendation?

Can anyone with a deployed Rails app recommend a reliable hosted SMTP
server that they use? I know that Gmail will let me send up to 500
emails/day, but I have an app that will need to send thousands of
(legitimate, non-spam) email per day.

I've heard that it isn't terribly difficult to set up my own mail
server, but we're a small company, and as such, we need as small of a
stack to maintain as possible.

I've looked around Google, but it seems very difficult to find a host
that provides a pre-configured SMTP server with flexible daily sending
limits. Probably because many of the people that would want something
like this are spammers.

Thanks,
Bill Harding
http://www.williambharding.com/blog

Most of the Linux VPS systems I’ve worked with have sendmail installed, so you can use that with Rails instead of SMTP to send messages. I have no idea if that would handle your volume or not, but it certainly works great for us.

Try installing ZIMBRA on one of your servers.