Okay, seriously, you pronounce giclée [zhee clay]. The word is French in origin, so don't give it a hard "gi" and a long eeee at the end. Aim for a soft, short "zhe" for the "gi" bit and a harder "clay" for the "clée".
How do I know for sure, given I don't speak much French? Simple, I asked an expert -- About.com's French Language Guide Laura K Lawless, who kindly put together a vocabularly page on giclée that explains the meaning of the word and, even more usefully, a sound file where you can hear the word spoken. See How to Pronounce the Word Giclée. Be warned: There's also a slang use of the word you wouldn't use in polite conversation.
What is a Giclee Print?