Timin525 asked about porcelain tea sets, and this is a tough question.
I was looking for a tea set in the spring. We were working on table manners, and I had the idea of having princess tea parties where we would practice our best princess manners. I looked everywhere and couldn't find a tea set that would work. Everything was either super pricey or made in China.
So, I went with made in China. I bought the Fiesta Ware Style Ceramic Tea Set by Schylling ($20.00) from Peapods Natural Toys. And, the reason I was ok with it is because I know that Millie and Dan, the owners of Peapods, did extensive testing of their inventory to make sure it was all CPSIA compliant.
Fiesta Ware Style Ceramic Tea Set($20.00)
The girls love the set and use it all the time, and if they weren't busy squishing dinosaurs into soft dough, I'd get pictures.
Another option is a handmade tea set. Donna, who won the Advent calendar, is the artist behind Lady Madonna Pottery on Etsy. We have a teeny-tiny, doll-size set that she made, but there are different sizes, and they are affordable (the one shown is $25) - and, they are all safe.
There are also some hand-painted sets on Etsy, but there is no information about safety. If you are curious, search on child's tea set and ask.
If it wasn't so expensive (and it wasn't out of stock), I'd want this one from Mahar Drygoods.
Mushroom Tea Set ($140)