The ion (or possibly a neutral sodium, given its colour) tail has been visible since the 20th- I posted it on my web page here:
http://members.ozemail.com.au/~loomberah/mcnaught.htm
It is reasonably obvious, even in twilight.
The comet is also visible to the naked eye in the mornings, I posted a pic of that yesterday, same URL as above.
cheers, Gordon