AirNav: 5W5 - Triple W Airport
Look under the "Airport Communications" section about the middle of the page.
122.700 = CTAF (Common Traffic Advisory Frequency) Any movement at the field, landing or departing, is called out on this frequency.
The remaining 3 frequencies are for AWOS (Automated Weather Observation Station) frequencies, I'm almost positive that these broadcast weather conditions, but I'm not for sure... (My home airport uses ATIS, so I'm not familiar with AWOS)
Point being, I would concentrate on 122.700 to keep up with what's going on around the airfield, and keep the 3 weather freqs locked out, so they're not constantly going off, but are there if you want to check for weather advisories or NOTAMS.
Hope this helps!