nVIDIA GeForce 6800 Ultra Video Card when was this video card released
to the public? And where can I buy this video card online where it
isn't not available or sold out?

NVIDIA's press release here
(http://www.nvidia.com/object/IO_12687.html) for the 6800 announcement
was on April 14th. In the release it states that availability for the
card is due 45 days from the date of the press release. So roughly
June 1st, 2004. As always with computer parts releases, availability
is hard to come by at the beginning of a release date. So while cards
might be technically available on a specific date, the chances of
obtaining a card on that date are fairly slim.

You can buy cards based on the 6800 chipset from newegg.com. They have
quite a few that aren't out of stock.

ASUS 6800
http://www.newegg.com/app/ViewProductDesc.asp?description=14-121-172&depa=1

Gainward 6800
http://www.newegg.com/app/ViewProductDesc.asp?description=14-128-197&depa=1

Outpost.com also has a few in stock:

PNY
http://shop4.outpost.com/product/4082622

Leadtek
http://shop4.outpost.com/product/4098422

Just realized you said Ultra.

MonarchComputer.com
BFG 6800 Ultra
http://www.monarchcomputer.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=M&Product_Code=190436&AFFIL=FRG&NR=1

Newegg.com is supposed to have the ASUS Ultra tomorrow (8/27)
http://www.newegg.com/app/ViewProductDesc.asp?description=14-121-175&depa=1

Maybe try here:
http://www.computerbrain.com/cbisys/buy.asp?main=VideoCards&title=BFG_Technologies&id=112

Failing that you can go through the listings here:
http://froogle.google.com/froogle?q=6800+ultra&btnG=Search+Froogle

Good luck!

Unless you're truly desperate to get your hands on one of these, I
would recommend holding off for a bit, until supply expands to meet
demand... as it stands, these cards were released with an MSRP of no
more than $500.  I doubt you'll find one for anywhere near that, as
the onslaught of demand for them has driven prices up alarmingly fast.
 You can get ahold of one on Ebay, but it'll set you back $600 or
more, and even the bigger, more reputable chains are adding a tidy
markup to new ones.  (I came across one the other day selling them for
$750 apiece, and they were still selling!)

If you were to give the furor a couple of months to die down, you
could presumably save yourself hundreds of dollars.