These authors argue in a peer-reviewed journal these gullies could be formed from liquid water under current Martian conditions:

Water Flowed Recently on Mars, NASA Scientists Say.
By Robert Roy Britt
posted: 24 August 2005
"If liquid water pops out onto Mars' surface, it can create short gullies about 550-yards (500-meters) long," Heldmann said in a statement. "We find that the short length of the gully features implies they did form under conditions similar to those on present-day Mars, with simultaneous freezing and rapid evaporation of nearly pure liquid water."

Formation of Martian Gullies by the Action of Liquid Water Flowing under Current Martian Environmental Conditions.
American Astronomical Society, DPS meeting #37, #32.10
"We find that, contrary to popular belief, the fluvially-carved Martian gullies are consistent with formation conditions such as now occur on Mars, outside of the temperature-pressure stability regime of liquid water.
...our model indicates that these fluvially-carved gullies formed in the low temperature and low pressure conditions of present day Mars by the action of relatively pure liquid water."

Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions.
36th Annual Lunar and Planetary Science Conference, March 14-18, 2005, in League City, Texas, abstract no.1270.

Formation of Martian gullies by the action of liquid water flowing under current Martian environmental conditions.
Journal of Geophysical Research, Volume 110, Issue E5, CiteID E05004.

Another scientist has independently observed these currently forming gullies occur in a region shown to have high water content by GRS readings and to have very youthful looking gullies, near Kaiser Crater:

Martian dunes hide water secret.
Scientists have found evidence that large amounts of water-ice hide within massive sand dunes on Mars.
"If you're looking for a source of water for any future landers," said Dr Bourke, "I am advocating that you march up to your nearest sand dune."
Monday, 5 September 2005, 19:31 GMT 20:31 UK

I'm suggesting the dunes in this area of Kaiser Crater and the rim of the crater itself are good places to look for additional currently forming gullies.

Bob Clark

Image of the Kaiser Crater with very youthful gullies.