Places:

• Cactuar Island- An uncharted island far south of cosmo canyon. Fight cactuars here
• NE island- An uncharted island in the NE (duh). Get knights of the round here
• A cave on the same continent as Wutai. On the little tip that extends east. (Mountain chocobo)
• A cave that is on the topmost of the long islands in the SE. (Mountain chocobo)
• A cave north of North Corel. (Black chocobo)
• Lucrecia's cave is west of the gold saucer. (Gold Chocobo, Submarine)

Items:

• Masamune blade- Found in the speed arena in gold saucer after getting over 4500 points. Has no purpose
• Combat Diary- Gotten after fighting in the special boss battles in battle arena. Has no purpose
• Tissue- Gotten after winning/losing a normal battle in battle arena. Can sell for 25 gil
• Super Sweeper- Gotten in speed arena after 3000 points. No purpose
• Guidebook- Morph the ghost ships in the underwater tunnel thing in the underwater reactor in junon. Trade in at far right house, 2nd floor in kalm for underwater materia
• Desert Rose-  After killing Ruby(Red) Weapon.  Give to same guy at kalm for gold chocobo
• Earth Harp- After killing Emerald(Green) Weapon. Give to same guy at kalm for master summon, master magic, and master command materias
• Cursed Ring- In mideel (before destruction) Get key from behind guy on balcony to the far left. Take key to weapon shop. Open door. Weapon shop owner gives to you. Gives +30 to all attributes. Gives 60 second counter before death on equipped character.  I don't know if you can uncurse or not, please tell me if you can.
• Money Card- Supposedly gotten from a clock in Kalm.  Purpose: ?? Supposedly used to give you unlimited money
• 1/35 soldiers. Heard that these were Sephiroth clones. Also heard that when all 12 are used in conjuction with the masamune blade and given to the guy you gave mythril to, something will happen. Gotten from snowboarding time trial. must get under 58 seconds.

Info:

• If any of your characters gets to 7777 hit points, they will go into a mad fury. Every single one of their attacks will do 7777 damage, and they will continue attack non-stop.  You have no control over their actions. At the end of the battle, that character's hp will be reduced to 1. Their hp can be reduced to 7777, healed to 7777, or have certain materia combinations which make sure that that character has exactly 7777 hit points.
• This one is kinda useless, but hey oh well. You can sideswipe the airship. Just simply hold down the ok button, and push left while holding down R1, or vice versa.  The ship will start flying sideways!
• When you are parachuting into Midgar, you can do little tricks by pushing different button combos
• Ok, this one isn't really secret, but it's not easily found out. The more counter attack materia you equip on a character, the more times they will counter attack when they are hit.
• Sorry for all these not-so-secret ones, but here's another. I had always thought that there were only 3 save spots, and therefore had to overwrite one of my games when I started a new one. Little did I know, that if you scroll down the save menu, you get many many more files.  Although the more games you save, the longer it will take to load up the memory card.
• In the gold saucer wonder arena, on the snowboarding game, there is a time trial. In order to access this, just get at least a good in each of the difficulty levels. The next time you play it, there will be a yellow balloon near the beginning of the course. Get it and there will be no obstacles in any of the courses.
• Did you know that if you cast the hades materia on the tentacles of the ruby weapon, you will slow them, poison them, and even paralyze them for a short while. Although after you do this, the tentacles get really pissed and will attack you with non-normal spells, such as shadow flare. If the tentacles are casting this along with the weapon, you have alot to worry about.
• Ok, this one doesn't impact the game or anything, but it should help clear up the storyline.  Many people ask me how did Sephiroth get into the north crater, and who was the Sephiroth that you were chasing around? Well, when Sephiroth stabs Cloud, and Cloud throws him over the bridge, the mako energy there must have carried him all the way up to the northern crater and deposited him into that crystal.  As for the Sephiroth that you were chasing around, that was probably a phsycic projection of himself. Oh, and as for the voice that you hear in the beginning of the game in Cloud's head? That's Sephiroth.  In the end, you find this out because Cloud goes into his mind and has a final showdown with Sephiroth