Regarding the poor man's sous-vide post from yesterday, it looks like boiling Ziploc bags is not recommended. From a consumer specialist at S.C. Johnson & Son (makers of Ziploc), "Ziploc bags are not designed or approved to withstand the extreme heat of boiling and therefore, using Ziploc bags to make any recipe that requires the bag to be boiled is not recommended." The plastic can melt at the temperature, and who wants to eat food merged with plastic?
Of course, if I'd read the recipes more closely, I'd have realized the salmon I was keen to try out doesn't even call for the faux sous vide prep, and is just slow cooked in the oven. The only recipe that calls for the use of freezer bag is the slow-poached shrimp, and that only wants water brought "to 150 degrees, just below a simmer." So you might be ok if you keep the temperature low, but consider yourself warned. [thanks Allan!]