Today is the big day when ISON flies by the Sun ("perihelion"), and all eyes are on NASA's SOHO spacecraft that is watching the event first-hand.
For up-to-the-minute web resources, I recommend the following sites.
Google Hangout with NASA
Sky & Telescope
NASA Comet ISON Observing Campaign
As of 7:00 am pacific time, it seems that the brightness of Comet ISON dropped somewhat, as reported on Spaceweather.com and Sky & Telescope.
There is concern that the very active Sun could release a Coronal Mass Ejection (CME) as ISON is at closest approach and this would be a very substantial threat to ISON's survival.
As of 8:30 am pacific time, there is speculation that the brightness is falling rapidly indicating that the comet is considerably vaporized and might not survive perihelion.
As of 10:00 pm pacific time, it's possible that a small part of the comet remains intact, but overall it seems that the comet has been mostly decimated in the trip around the Sun.
As of November 30, it looks like Comet ISON has really disintegrated. Very sad indeed. But it was a fun to have all of the excitement and close watching of this rare event. Here's to the next big comet headed our way!
A Short Eclipse Mega-movie Already Available
1 hour ago