Yo all! An year ago I did one discovery... 8-)
Some guys got my experience and did such FAQ:
--- Don Miguel http://rpgmaker.chat.ru/ ---


====== Tile Swapping+ v1.1 ====
	By The Brain

Issues with tile swapping:

Each tile set (Mchip0 - Mchip3 is one set) must have the same attributes.
Meaning, put flat land in the same slot on each set.
This means lining up the sets, tile by tile.
this will take some time, but once it is done, you can swap you new set
in for the old set (explained later). My suggestion is take the set you
want to swap in and clear it and save it with a different name.
Then open the tiles back up and copy/paste each 32x32 tile in.
Remember to look at where you paste into.
Most paint programs will tell you where you are pasting.
Make sure the number is divisible by 32 (except 0,0 of course).
Each tile file (Mchip0 or Mchip5 ect) must be named with 6 characters.
Each tile file (Mchip0 or Mchip5 ect) must have a .atr file.
Just copy the original .atr files and rename them to match your new file.
e.g. if you replace Mchip0 with Mchip4, take Mchip0.atr and copy it and
rename it Mchip4.atr. This will avoid any confusion.
When ever an attribute is changed in game, save immediately and then open a map with
a different tile set and change the attribute of the same tile slot.

The Technique:

First, be sure you back up your .rpg file before you do this.
After you have your tiles organized by attributes, open your .rpg file in wordpad.
Search for the name of the map you want to swap tiles on (e.g. castle1, forest1, dungen1 ect)
When you find it, look about 4 lines below it and you should see Mchip0-3 listed.
Now just change the Mchips to what tiles you want to use (e.g. Mchip0 becomes Mchip4.)
Now save as a text document.
Next, open RPG95 and load your game and open the map you just set to tile swap.
You will need to click on a different tile palate to refresh the tiles you are using.

Warping into the Map:

To get the tiles to refresh when you warp into the map do the following:
	Fade to black
	Warp to map
	Battle
	Fade out of black

Now you should be on your map with the different tiles.
Remember you have to do this every time you warp to a map with different tiles.
Also, the battle is what refreshes the tiles, the fades is just to make it look good.

--- And few words from Don and his friends: ---
P.S. Get Unlimited Tilesets demo "BMVDEMO.EXE" from http://rpgmaker.chat.ru/ 
	and examine it.
P.P.S. You could also get Hex-Editor from WWW.ULTRAEDIT.COM

P.P.P.S. Gemin-eye: Ok, after countless attempts at editing my TileTry.rpg file
 (the test maps i wanted to try the tileswapping on) I have come to the
 conclusion that it cannot be done with wordpad. I had to get a program called
 UltraEdit, Don mentions it in the Unlimited Tilesets Faq (WWW.ULTRAEDIT.COM),
 with this little proggie you can change the Mchip# and it also changes some
 other number too, i guess thats where all the difference is made. At first
 when you open the Ultraedit you\'ll see a bunch of double digit numbers,
 over on the far right scroll down till you see the 
 mchips....mchip1....mchip2...etc..just click on the number on the mchip
 you want to change and the whole line lights up and one of those Double
 digit numbers will change with the change of the mchip#. Then just close
 it and it\'ll ask you if you want to save the changes, click yes. Make sure
 you have the extra mchip(s) in the gam.rpg folder when you open it. Cross
 your fingers and hope you did it right. :]