actually, the German pronounciation of his name, specifically the u w/ an umlaut, would be pronounced more like "Muu-ler" (sort of like "moo-ler" but with the first syllable dropping slightly in pitch towards the end).  That said, it's fairly common for German language speakers to replace a u w/ umlaut with "ue" when typing as accented characters don't necessarily translate well (different character sets, etc). I don't think "ue" is the best representation/translation of the sound it's supposed to imitate, but that's just my opinion.