SNES 9X - This is the best emulator to use. It will let you play the game and see what needs to be translated. You also need this to play the game even if you don't plan on translating it.

UCON - Even if you're not going to translate, you still need this. It lets you apply IPS patches, which modify the ROM to be in English.

Snes Sprite Editor - Lets you edit sprites in 1, 2 or 4 bitplanes. If you don't know what that means, check out the Guide to Translating SNES ROMs by Shadow in my Documents section.

X-Char - I haven't used this. It was the first Sprite Editor available, but the one above is the best. It is powerful, but the way it lines up the tiles makes it hard to use.

X-Late - This is a hex editor modified to assist in translating. I haven't used it.

Hex Workshop - This is the undisputed best Hex-Editor around. You need this to edit text in the ROMs.