I was playing the game the other day on my Wii, and reached the part where you have to fight Belome again. Before that though, you have to get a fortune and then go on with the level from there. One fortune I got took me to a room where there were a few flowers and a bunch of frog coins. Belome was blocking the door and told me to find a key and he would let me in the room. For future use, where is this key located?

It's in plain sight in the town you're about to arrive at (Monstro Town).

But is that not the key to get into the Dojo to face Jinx, or is that door ever locked? I forget.

If that is the key for this part, how the heck do I get it before I face Belome? You go to Monstro Town after this part of the game.

You can return to the dungeon at any time. There's a door in Monstro Town that can't be opened without a certain item. If you open it, you'll encounter and get into a battle with Culex.

Well then. I always thought that key was used for something in town. Guess I never clued in. I get the key every time I play the game, but since I didn't know what it was really used for, I never knew where it went. I guess I will have to go back after the Volcano.

Unrelated this is but related to game secrets..

When you get to the end of the Palace, you fall off the edge and keep falling until you land infront of the area where you go to the Hot Springs. On the way down you pass a bunch of chests. How do I get these?

Remember the vines you used to climb up to Nimbus Land? You need to perform a few tricky jumps or find hidden tiles to get on the ones that are to the left of the screen at a certain point.

i think your supposed to kill the purple thing inside the sealed door, which you get into by getting the shiny rock, then the key might fall off from the edge. but i'm not sure...

That's not how you get the key. If you repeatedly talk to the thwomp in one of the rooms, it will eventually fall off.