The search function is your friend for tons of info: http://www.beeradvocate.com/community/search/32205621/?q=orange&o=date&c[title_only]=1&c[node]=8
I'm using some this weekend in a Belgian IPA. 1 oz at last 5 min of boil. Any longer and it starts to get harsh/bitter
We brewed a grapefruit sculpin a couple of weeks ago. After working with the grater for a half hour and getting only .5 oz of grapefruit zest, I opted for the garlic press to process the rest. Much quicker. Grapefuit zest was added to secondary at same time as dry hopping. Bottled yesterday. Eagerly awaiting the results.
I bought sweet orange peel for a blue moon clone and added 15 g to a 3 gal batch at flameout. One of my fastest kegs ever to kick, just right for summer.