I can't tell you what DIA's landing fees are, but the computation of the fees themselves is fairly standard throughout the US airport management industry.
Landing fee's are measured on a per 1,000/lbs of an aircraft's gross landing weight. Here at MSY, that rate is $3.51/1,000 lbs for signatory carriers (those have signed lease agreements directly with the airport), and $4.04/per 1,000 lbs for non-signatory carriers (those that don't have leases).
As an example, if United flew an airplane with a gross landing weight of 100,000 lbs into MSY, their landing fee would be $351.00.
How an airport arrives at a specific landing fee rate is rather complicated. It has to do with anticipated revenues from all airport tenants to the airport operator (parking garage, concessions, limos, taxis, space rentals, etc). It gets compared to anticipated total expenditures. The difference is made up via the landing fees. That's why some airports may charge a higher landing fee than others.
Tom in NO (at MSY)
"The criminal ineptitude makes you furious"-Bruce Springsteen, after seeing firsthand the damage from Hurricane Katrina