Can I remove the "Powered by" link
Yes, you can remove it. However, it would be great if you can promote JReviews to everyone you know or provide credit in some other way to help us with the traffic to our site so we can providing excellent support and upgrades.
You will need to edit the file:
And remove the following code:
<div style="margin:20px 0 20px 0;text-align:right;font-size:85%;"> Powered by <a href="http://www.reviewsforjoomla.com/" title="Joomla CCK and Reviews">JReviews</a> </div>
Do not change the text to Powered by XYZ, it goes against the license terms.
You can make this change once and not worry about it on upgrades by using the JReviews Code Overrides feature.