Storing Prints
From The Giant: The Definitive Obey Giant Site
In general, prints should not be left in the tube in which they are shipped, but should be stored flat. The best possible environment in which prints can be stored is a light-tight vacuum, but given that most people don't have such storage units available (though i'm certain they exist) the things that you would like to avoid are sunlight, heat, moisture, and non-neutral pH. So, whatever storage solution you use, it's best to keep them away from heating elements, windows (if they are not in a sealed environment), and places which might be exposed to moisture (near bathrooms, kitchens, water heaters, etc.).
Several options are available for storage. On thing you can use is a portfolio. Several members (including myself) use the Alvin Prestige Presentation Cases though there are several other brands available. Portfolios such as the Alvin are nice because they keep out light and provide a neutral-pH environment for the prints, they are easy to transport, and they provide quick access to all the prints kept inside.
A second option is to use a storage box, such as Eternity Archival Storage boxes or those made by Light Impressions. These also keep out light and are neutral-pH. They are excellent for storing large numbers of prints and for long-term storage. Some disadvantages are that they aren't great for transporting prints since there is no way to secure the prints in place, and they also do not provide quick access to all the prints since they are generally just stacked on top of each other in the box. If you're worried about prints rubbing against each other they can be separated with acid-free tissue or higher-end storage materials such as glassine.
A third option is to use mylar sleeves with an acid-free backing. You can get cardstock backings which will leave the whole thing flexible or foamcore backings which will keep the sleeve rigid. These sleeves are available in numerous sizes from sites such as bagsunlimited.com. They're fairly expensive though, especially if you get the foamcore backings. To allow easy access you can also get a rack to hold the sleeves, or just stand/stack them in a safe location.
A fourth option is to store prints in tubes. This should be a last-resort option as it's much better to store prints flat, but there are some prints which are just too large for most peoples' flat storage systems. If you store prints in tubes make sure they are rolled in an acid-free barrier paper to prevent contact with the tube (which is probably not acid-free) and also prevent the print from rubbing against itself if you move it around. It's also better to use a large-diameter tube so that the print is not rolled tightly. The tighter and longer a print is kept rolled, the longer it will take for it to flatten out when it's taken out.