Sigh.....
okay, after you beat Blaine Bill the PokeFreak asks if you want to go to the 3 islands. Say yes and he'll take you in his cool superfast boat. You land on island 1, where Moltres is. THE OTHER TWO ARE IN THEIR OLD LOCATIONS. You can go to islands 1-7 LEAGALLY, although 4-7 are accesible after beating E-4 First Wave (i say that because their Pokemon are different after fixing the machine) Nothing elce to do here yet. There is a big machine in a huge Pokecenter, whice after you beat E-4 First Wave, you can fix by finding the Ruby and Sapphire Plates. Also, on island two it is like a town and someone asks you to find their daughter on Island 3. On island three, some bikers have her, and you have to fight them. I probably have everything wrong so go to gamefaqs.com, click on GameBoy Advance, Pokemon Fire Red should be on the top ten FAQs, but i went to leaf green by looking it up. The first FAQ has info, although the second FAQ has more.
List of GSC Pokes i know of:
Slugma
Sneasal
Larvitar(YES!!!!!!! What version has this, does anyone know)
uhh...Hophip....
Yeah there's probably more though...
Illegally:
There are also Islands 8 and 9, where Ho-oh, Lugia, and Deoxys (yes, Deoxys!!) are obtained. There is currently no way to get there besides codes. Ho-oh and Lugia are both on island 8 (do not know if getting both is possible) and to get Deoxys you have to solve some stupid triangle puzzle on island 9. Also, Deoxys looks different in Fire red than he does in Leaf green and both of those look different from Ruby/Sapphire. Also (get this), he has different base stats in each!!!
FR: 50 Hp,180 Att,20 Def,150 Spd,180 Sp.Att,20 Sp.Def
LG: 50 Hp,70 Att,160 Def,90 Spd,70 Sp.Att,160 Sp.Def
R/S: 50 Hp,150 Att,50 Def,150 Spd,150 Sp.Att,50 Sp.Def
So FR's has great attack, horrible defence, and LG has great defence, moderate attack, and R/S is a more balanced FR.
Also, Team Rockets new and improved base is on one of the Islands!!!!!!!
Oh and on the unobtainable Pokemon list you said Corsola, which is untrue because Corsola is in Ruby and Sapphire...which can trade with these....
I don't want to give my Pokemon to that game after I get Leaf, because after seeing the screenshots, i have decided that FR/LG is superior to R/S!!!