The FDA has posted a new webpage in August 2006 with a readable and fairly comprehensive set of guidelines for selecting fish for safety and how to prepare it safely.  While this particular guidelines webpage does not offer a lot of details on omega-3 fatty acids, it is quite successful in its overview of the basics regarding fish and mercury (and PCBs), advisability of omega 3 fatty acid consumption, and especially clean and safe preparation of seafood without cross-contamination to other foods.  It also warns pregnant women, the elderly, and those with compromised immune systems on how to avoid Listeriosis infection, particularly from smoked seafood.  It is quick and easy to read through this page, and anyone with food preparation responsibilities in your household should read it.  You can find it at the following link: FDA fish and seafood safety guidelines.