You can change it to just about anything you want but there is no option available in the forum admin to do so. You have to do it by editing the spFoot.php file in your Simple:Press theme.

Before you do so you should create a custom theme so your changes don’t get overwritten on updates. The Codex article here http://codex.simple-press.com/codex/themes/theme-basics/creating-a-theme/ shows how that’s done.

You could even add your stuff and leave in the Simple:Press info in the footer.

If you just want to replace the text and link shown let us know what you would like it to be and we can give you some hints on how to change it.