Be sure to click SWITCH vs clicking the name of the page. If you click the name of the page, you'll just visit the page as yourself.
Now that you've clicked SWITCH, you'll notice in the upper right of Facebook that you are now logged in as your business identity vs yourself.
So, from here, go to your favorite groups, etc, and "like" and "comment" as appropriate. You'll notice when you "comment" the name listed is the company, not your personal name.
We feel this is an important method of "branding" your company through Facebook that is often over looked. Of course, you have to "like" and "comment" intelligently, else you might "brand" your company the wrong way.