Difference between еще and ещё?
Is there any difference among them?
That is correct. Eще is an acceptable (mis)spelling of ещё. Russian speakers usually don't care: we know when a е is a е and when it's a ё, but I find it irritating that the phonetic nature of Russian is given away so easily over something completely irrelevant these days: some historical typographic issues with typesetting ё.
From everything I've read, the two little dots above ё are sometimes left out by natives and are pretty much only used in children's books, dictionaries, and certain city signs for tourists. Natives would know whether it's suppose to be e or ё and don't need the dots to know to say ye or yo. So еще is just an acceptable spelling of ещё, but still pronounced ye-sch-yo. Ye-sch-ye would not be right and is not a word.