we make a hot version of our flagship ipa. we use about 30 or so habaneros for a 3 bbl batch, or we use a mix of peppers depending on what we can get from employees/customers. cut about half of the peppers in half, leave the others whole. put in a pot. cover with water, and raise to a boil. reduce to simmer for about half hour, or until you remember its on the stove. let it cool. put the pepper water (however much you feel you want/need) in secondary and bag the peppers and put them in. you could also just do it at kegging. or in your bottling bucket.
i should say that you do get some of the pepper character, but its mainly heat.