Im plaaning on using enterbrain tile set some one was offering. can i use it for my iphone rpg? if not
can i change the tiles a little to use it legally
No and no.
Probably not. There are non-RPG Maker versions (same tileset, different license) available for some of the tilesets. You would need to purchase one of those, but only a few are available.
Changing it a little does not change the license status.
you would have to change it a lot. like to the point if you looked at the resulting tile you would not be able to tell where it came from. In which case might as well start from scratch if you have to change it that much.