I think the most important thing is don't wait until it hits CNN to prepare. By that point, it's probably too late. If there are reports of a pandemic flu strain in the U.S., half the country is going to be scrambling to grab any supplies they can get their hands on. It's far better to be prepared in advance.

In this sort of situations, my first priority would be not to get the flu. There are lots of places selling 'Bird Flu Kits' with masks, gloves, etc., but I'm skeptical of their usefulness. The flu spreads through interpersonal contact, so the best solution is probably to lock the door and call your boss and tell him you won't be in for a few weeks. Of course the danger is that if too many people take this course, particularly those that work in public safety or basic infrastructure, we could end up with a real societal breakdown. If you have to have contact with other people, masks and gloves may be useful, but it's probably just as important to take your vitamins, drink plenty of fluids, and wash your hands regularly.

Beyond not getting the flu, the basic concerns are the same as they've been since time immemorial: shelter, food, shelter, water, and personal protection. The catch is you're going to want to be able to meet these needs without leaving the house, and in the face of disruptions to basic services.

Shelter: In a pandemic situation, I'd probably go with sheltering in place, so I'll already have a roof over my head. However, the electricity and natural gas may not stay on, so plan to deal with a lack of AC or heat. In a cold climate a wood stove would be great, but since I live in an apartment it's not really an option. I'd probably just have to go with sleeping bags and warm clothing inside and out.

Food: I've been trying to build up a supply of canned food sufficient for a couple of weeks. This mostly involves buying a bit more of the sort of stuff I eat anyway and just maintaining a bigger supply. In the event of a pandemic, I'll be eating a lot of canned soup and ramen, but I can probably go for at least two weeks at this point.

Water: This is the one I'm most worried about. I'm entirely reliant on the municipal water supply, so if it goes out, I'm in trouble. I've bought some 2.5 gallon containers of bottled water, with the goal of building up about a 30 gallon supply.

Personal Defense: Any sort of large scale disaster has the potential for civil disorder. A pandemic may deter some of this, since even criminals would be worried about catching the flu, but there are some people stupid or desperate enough to want to take advantage of the situation. How far you want to go with defensive preparations is really a personal choice.

I think that these four really cover what you need to stay alive during a pandemic flu situation, but there are a lot of other possible preparations that could make you more comfortable. For instance, lately I've been thinking about 'waste management' in the event the municipal sewer system goes out.