I know I have seen websites with them. I'll keep looking to see if I can find any. I just made mine with a die-cut machine and laminated them.
I just used a cool font that was "bubble-y" (for lack of a better term), colored it, mounted on construction paper, and laminated them- cheap and easy!
http://www.prekinders.com/classmanagement_printables.htm These are simple with pictures to go along. Scroll down.
thanks so much. I appreciate it. i need to get those permanent centers up and running this week or next.