Castelia city, on the first dock, talk to the guy in the lab coat
pansear
Fire stone evolves Pansear into Simisear.
You give it a fire stone
in pokemon black and white
in white two, you can find it in the desert resort
Petilil will evolve with a sun stone, pansage with a leaf stone, panpour with a water stone, and pansear will evolve with a fire stone.
it is in the desert near relic castle
Pansear evolves by Fire Stone into Simisear.
it evolves with a fire stone not by leveling up
So far (although I have completed White not yet Black) all I know are Pansage (Leaf Stone), Pansear (Fire Stone) and Panpour (Water Stone). Sorry if this isn't as helpful as you hoped!
how should i no
A fire stone is used on certain Pokemon to make them evolve. The Pokemon that evolve with a fire stone are: ~Evee ~Vulpix ~Growlithe