This plugin when activated automatically redirects all email sent through wp_mail/phpmailer to the user currently logged in or the site administrator.
The redirected email contains information about where the original email would have been sent to.
Use this plugin if you want to test email-sending features without actually sending emails our to anyone but yourself. I wrote this plugin to ease debugging with subscribe2.
Since Version 1.2 you can choose whether to redirect all email to the currently logged in user (default), the site administrator (only wpmu) or the blog administrator.

Mail Debug

Redirects all email sent through wordpress to the user currently logged in or the site administrator.

sitebase

Use a custom mail server to send mails in WP. This way you can also send emails when testing on your local server. Make sure to follow us on <a href="http://twitter.com/Sitebase" title="Follow Sitebase on Twitter" rel="nofollow ugc">Twitter</a> for updates and more.

MailBase

Configure a mail server you want to use for mailing in WordPress

Mail Debug vs MailBase