SMTP Server

Hello, I recently installed xwiki on my local machine for testing. The goal is to install xwiki on the company server at a later time. I had no troubles installing xwiki but I have serious trouble getting the email notification running. I activated the email notification (XWiki.Preferences) and set up the smtp server on "localhost" and the admin email to "jgehbauer(a)gmail.com".com". Unfortunately, I did never receive any email. I tried other smtp servers like smtp.gmail.com or smtp.comcast.net but it all seems not to work. I do not receive any email. I am running Tomcat 5.5.17, MySQL 5.0.19, and xwiki 0.9.840 on a Mac OS X operating system with a Firefox Browser. At some point I received the error message that the connection was refused. But that only happened once. I would appreciate any help on setting up the email notification. Thanks. Cheers, Jens