This link has a list of adjectives that are usually put before the noun: http://italian.about.com/library/fare/blfare129a.htm
As mentioned there, they can and sometimes must be put after the noun in some cases. Also, some adjectives slightly change meaning depending on where they are placed: "Questa è la mia casa" (this is my house) vs "Questa è casa mia" (this is my home), or "Un alto ufficiale" (a high official) vs "Un ufficiale alto" (a tall official). Sometimes it's pretty much indifferent, e.g. "La settimana prossima" vs "La prossima settimana" (next week).