MySQL service is grey under Server Admin
The plist which serverAdmin uses to store the status of the service is missing some keys.

take a look at /Library/Preferences/com.apple.MySQLService.plist

it should look like:

&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;
&lt;plist version="1.0"&gt;
&lt;dict&gt;
    &lt;key&gt;activeDBPath&lt;/key&gt;
    &lt;string&gt;/var/mysql&lt;/string&gt;
    &lt;key&gt;selectedDBPath&lt;/key&gt;
    &lt;string&gt;/var/mysql&lt;/string&gt;
    &lt;key&gt;serviceRunning&lt;/key&gt;
    &lt;true/&gt;
    &lt;key&gt;serviceStart&lt;/key&gt;
    &lt;date&gt;2011-07-27T14:24:23Z&lt;/date&gt;
&lt;/dict&gt;
&lt;/plist&gt;


Probably yours is missing the serviceStart key

I've had this happen before, though I don't know why.