I have comments set to require approval, but need a way for either the admin or the author to be notified that there is a new comment waiting for approval. Is there a plugin for it, or is it already built in (which i would image it is)

Ill have to look at 2.5.5 to see, not sure.
for 2.4.1, check out k2autonotify at K2joom.com (will be updated for 2.5.5 hopefully in the near future)

I am unfortunately using joomla 1.7 (of which its not compatible), so really hoping its available in 2.5.5

Is there any other route to achieve notification of comments? It really sounds like something that would be built in! Im unfortunately using joomla 1.7, so can use the addon module. Please, there must be another way to achieve this!!

As far as i know, unless you use another commenting system, there is not.
I am also waiting on the upgrade...

Does anyone know if v2.5.5 addressed any of this?

He's working on it
see his home page post at www.jiliko.net/

Thanks William. Looks like Mr.Nolbert is back hot on the trail!

Work and tested for K2.5.6 with recaptcha ON or OFF and joomla 2.5.2 and google email account.

1. Site-configuration-server-post (or edit configuration.php):

public $mailer = 'smtp';
public $smtphost = 'smtp.gmail.com';
public $smtpsecure = 'ssl';
public $smtpport = '465';
and add your google email login and password:
public $smtpuser = '';
public $smtppass = '';

2. Edit file components\com_k2\models\item.php

Near line 1018 seek last 3 line of end of function comment() :