What to use to tile a cement bird bath?

You can use anything from broken china and stoneware to the more expensive glass tiles or better yet, make your own "tiles" from glass that you cut into the squares yourself.

There are also several sellers on Ebay and similar sites that sell the glass tiles or squares already cut for you.

Hope this helps!

Here is the link to the Ebay glass mosaic tiles:

http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=glass+mosaic+tiles&_sacat=See-All-Categories

Here is one more that's broader search...mosaic tiles. This includes glass, stone and such.

http://shop.ebay.com/items/?_nkw=mosaic+tiles&_sacat=0&_trksid=p3286.m270.l1313&_odkw=glass+mosaic+tiles+for+birdbath&_osacat=0