The study will determine the pharmacokinetic profile of indinavir, given as single drug or in combination with zidovudine and lamivudine. It will assess the preliminary antiviral and clinical activity by monitoring clinical status, viral burden in plasma, and markers of immunologic status. Based on safety and preliminary efficacy results from studies performed in adults, we will study three dose levels which are expected to result in drug levels above the IC95 of HIV-1 for all or most of the dosing interval.