They're sometimes called African walking frogs, (kassina senegalensis) but are in the reed frog family (or hyperoliidae). Hope I didn't get you all excited under false pretenses, that was what I was told they were, in the reed frog family I mean.

Here's a link about them, I haven't actually had it officially confirmed that's what mine are, but trawling the net this is the closest resemblance I could come up with. The guy in the pet shop just said the were African running frogs. I thought they were kassina macualta at first, but mine lack the red striped legs.

African Treefrogs: Hyperoliidae - Bubbling Kassina (kassina Senegalensis): Species Accounts