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Hiya! If by the format you mean the actual tileset sizes, to my knowledge there's no way to do that with binary hacking tools. However, you might be interested in pokeruby, decompiled Ruby - using that you can edit the source code. I've never done it personally but I know it's possible to change the tileset format to FR's using that.
If it's just the inserting part you might want to check out this tutorial for tile inserting. Once you've got the hang of it you should be able to get the FireRed tiles moved over to Ruby without too much bother =)