"He is already here."
Translation:Lui è già qui.
No it is not correct because adverbs usually follow a simple verb form. (Mangia sempre il pollo. = He always eats chicken.)
Find out more about placement of adverbs at the end of this article http://italian.about.com/library/fare/blfare139a.htm
Thanks for the answer! If I have read correctly, "Lui è già stato qui" would be right, wouldn't it?
Yes you got it, "già" in compound tenses goes between auxiliary verb (è) and past participle (stato)