Question

I've walked about everywhere in the forest in Pearl, but I can't find the mossy rock to evolve my Pokemon .-.

Answer 1

This map should help. Its in the middle, towards the left.

Comments

Now how did I miss that... Do you know what level my Eevee will evolve into Leafeon at (if it's at level 1 with NO exp right now?)

---

Level 2.
Also, apparently you can Level it up anywhere in Eterna Forest,

Answer 2

It is in the South West of the Forest, but you can evolve Pokemon (Like Leafeon) anywhere in the forest

Comments

No, you have to level it up near the Mossy Rock...

---

Wrong

"A small Moss Rock is located in the southwestern section of the Eterna Forest in Sinnoh, to the west of a formation of trees that resembles a sideways L. Eevee will evolve if leveled up anywhere in the forest, except for the Old Chateau and the path that encompasses the outskirts of the forest."

-http://bulbapedia.bulbagarden.net/wiki/Moss_Rock

---

Huh.
Never knew that before.