Here's the NASA press release announcing it:

NASA's Phoenix Lander has an Oven Full of Martian Soil.
http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080611.html

Here's a Space.com article discussing it in more detail:

Mars Soil Sample Finally Delivered to Phoenix Instrument.
By Andrea Thompson
Senior Writer
posted: 11 June 2008
03:21 pm ET
http://www.space.com/missionlaunches/080611-phoenix-mission-update.html

There is a link to the audio teleconference on Wednesday, June 11th
on the NASA press release page that discussed the successful filling
of the TEGA instrument.
It is mentioned during the teleconference that the soil showed very
fine imprints from the underside of the scoop. They suggested the soil
was like a very fine powder, like flour. But what was confusing was
that if fine powder why did it not fall through the sieving grid. And
why did it stick to the smooth surfaces of the lander?
Later it's mentioned that their experiments with different soil
analogues still haven't duplicated the stickiness as seen at the
Phoenix site. There was "something missing", they said.
That the soil sample was able to pass through the sieve after being
exposed in the Sun on top of the lander for some time led to the
suggestion that water/ice in the sample evaporated/sublimated off.
The temperature and pressure conditions there are within the range of
liquid water brines at least temporarily. Maybe the difficulty in
modeling this problem is the resistance to accepting the presence of
liquid water brines as a legitimate possibility.

If it were small amounts of liquid water even in the form of brines
then that would fit perfectly since the small clumpy particles would
be small amounts of mud.
Note also that mud would also leave fine detail of the imprints from
the scoop while at the same time being sticky, unlike the fine powder
explanation.

Bob Clark