My basil is dying fast

Yesterday the thing looked very wilted so I gave it an extra watering,
but today it looks worse and the entire plants looks like it is dying.
The stems are browning from the root upwards. It looks brown to
darkish brown. It looks like whatever is moving up all the stems. SOme
branches appear to be shedding their leaves. I found a pile of dead
leaves under the branches.

Sound familiar to anyone.
DiGiTAL ViNYL (no email)
Zone 6b/7, Westchester Co, NY, 1 mile off L.I.Sound
2nd year gardener
http://photos.yahoo.com/ph/royalfrazier/