We work on a different sound weekly (vowels, diagraphs, blends) and the words used in the "Slide your Words" center correlate with what we are working on that week. There is also a recording sheet that goes along with this center that is available here.
This center can be good practice at home too!
Here is another link for some of the actual strips that are used with the words and graphics. All you have to do is print on cardstock, laminate, and cut into strips.
Hope this is helpful to you, like it is for us :)