Are late fees considered taxable income?

[Peter M.]

I know deposit money is not considered income unless you keep the deposit at the termination of a lease but how do late fees factor in to taxes? Are they simply added in with the rest of your rent rolls? I guess the same concept can be applied to application fees. With application fees you are using that money to pay for a credit check and the time to run the application; late fees are paid for the time to track down tenants and collect. Any insight would be appreciated.