Configuring Nagios Alerts to send Email Notifications

Hello. I am not new to nagios, but new to confiuring it. At my previous job we had and used nagios for monitoring, Now at my new job I built and configured one myself. I have it running rather well, monitoring about 15 servers and about 40 services, the one thing I am having problems with it having it send out email alerts. I am not sure where to start. Here is the catch, the mail server is not on the same network as the server subnet and it needs to use smtp relay to send out the messages. I have been reading thru the post and there are a lot of experienced admins here, so I am confident someone will know the answer.

Thanks in advanceā€¦

Tim

PS. Sorry, I am running the latest stable on Ubuntu Server 7.04 with all the patches and mailx installed via apt-get mailx.