Parafilm has been mentioned on this forum before, search "parafilm"
A good method for long term storage of cork top bottles is to wrap with Parafilm: http://en.wikipedia.org/wiki/Parafilm
Parafilm will seal the bottle so that alcohol and congeners do not seep out and air (oxidizers) does not seep in. It will protect the cork/seal from degradation.
It is debated on whether air introduced into a bottle when sampled will degrade whiskey. Some people evacuate air with a stream of nitrogen or argon gas before sealing an opened bottle. I do not. Also, I DO NOT recommend the use of vacuum pumps for evacuating air.
Most twist top bottles seal sufficiently for long term storage and do not require further seal.
It is not necessary to use Parafilm on modern unopened cork top bottles sealed with wax or heavy (like lead) foil. If the cork is outer sealed with plastic or thin (aluminum) foil then consider wrapping with Parafilm if one plans on storing bottle for many years.
Proper use of Parafilm. Cut a strip off the roll. The strip has paper backing, which is tossed. Stretch the film as much as possible without breaking and wrap the bottle top. Press the film down with finger to further enhance seal. One full wrap is probably sufficient, but I do more than that for precious material. Parafilm is cheap. A roll lasts forever, so I don't mind wasting it.
One source for Parafilm is ebay dealers. Don't bid the auctions up. There are tons of it available so if bidding goes up, just wait for the next listing.
Even with Parafilm, I recommend storing bottles in a cooler environment, like a basement.
Another suggestion is Sharpie pen if one wants to record the date or mark a fluid level of a bottle. Sharpie will write on glass but can be removed with strong alcohol if one wishes to wipe it off. I use a more blunt tip and not fine point so that it's easier to read.