You need at least 7 days to do this, any less than seven can result in undesireable quality. Even 5 days in water is not enough – you need seven!!!
Plop in your freshy cut buds (or schwag, whatever, but fresh buds work best) into enough water to completely submerge the buds. The buds will float to the top for the first few days of this, so you need something to hold them down (a block of wood, a plate, etc). Change the water every day for 7 days, any less than seven could result in undesirable results (trust me). Try not to disturb the buds when changing the water as plant material can break off more easily (read: trichomes). Always keep the lid of the cooler open, do not seal off the container.
The water may take on a yellowish/greenish (even brownish) tint each day, more so as the bud becomes completely saturated with the water. It will probably also stink. This is good, as it is the nasty chlorophyl and salts exiting your plant.
After 7 days remove the buds from the water. They will be sopping wet, and can be dried relatively quickly. MPD (and many more of us) purchased a food dehydrator from wal-mart for about $40 and consensus tells us this may be the best method for drying. Put the dehydrator on the lowest setting and dry for about 5 hours or so.
Radiators and other low-impact heating devices can also be used. Users have reported hair dryers working with some success, as well as hanging the wet buds on a clothes line with a fan circulating air. The important thing to do is to ensure the buds dry quickly enough to not become moldy, but with as low-impact of a drying environment as possible.
