User activation link issue
I don't know if this is relevant for the Email Service, but you should use the (new since Craft 2.0) siteUrl config setting (recommended):

'.dev' =&gt; array(
    'siteUrl' =&gt; 'http://example.dev/',
    'environmentVariables' =&gt; array(
        'siteUrl' =&gt; 'http://example.dev/',
        'serverPath' =&gt; '/Users/foo/'
    ),
),

'mysite.com' =&gt; array(
    'siteUrl' =&gt; 'http://example.com/',
    'environmentVariables' =&gt; array(
        'siteUrl' =&gt; 'http://example.com/',
        'serverPath' =&gt; '/home/mysite_ftp/www/'
    ),
),

// ...


Or you set the Site URL setting in Settings → General to {siteUrl} (the custom siteUrl variable you set in environmentVariables).