Drying is basically just as the name implies. During this phase you're trying to get about 70-80% of the moisture out of the buds. Depending on the size of your crop and how you dry it, this process can take anywhere from 2 days to a week.

You don't want a fan blowing directly on your buds as this causes uneven drying, just enough to circulate the air in the room so you can prevent mold. Some people like to add space heaters, but in my opinion I think that quick drying or speeding up the process traps chlorophyll and pigments causing an uneven burn and a nasty "green" taste.

When are your buds ready to be cured?
Try to break the stem -
If it bends, they aren't ready quite yet.
If it breaks, get ready for the cure!

(Depending on how solid your buds are will vary the drying time)

Also, be sure to keep your buds in a dark place while they're drying/curing and in general as THC degrades when exposed to light.

The reason you cure is to get rid of the excess chlorophyll in the buds by "sweating" it out, as well as making more of the THC in the bud psychoactive.
See, when your buds are moist - all of the THC is in it's acidic form which won't get you high. The reason we dry and cure is for an even burn and to increase potency/taste.

To cure, you simply place your nuggets into a mason type jar. (a glass jar with an air tight lid, I wouldn't use plastic because I think it gives the buds a plastic-y taste/smell) DO NOT pack them. You want as much airflow as possible between them to prevent mold.

You don't want your buds too dry or the curing process won't take place. If they get too dry for some reason, just add a fresh leaf or a few fresh buds to the jar and they'll pull the moisture out.

-Check on your jar in 2-4 hours to see if there is any moisture build-up. If there is, open the lid for 5-10 minutes and store them back up.
-Check on them everyday for any moisture buildup, and if there is - go ahead and open the lid for 5-10 min. If there isn't, I would still at least open the jar every 3-5 days to let the excess gases escape.

You can cure for anywhere from 10-90 days and the potency and flavor WILL increase.

Here are some links

http://boards.cannabis.com/showthread.php?t=60954
http://www.norml.org.nz/article462.html