IDV is an effective anti-HIV drug, but it can be difficult for patients to take. For IDV to work against HIV, it must be taken 3 times a day at a high dose and with a certain diet. Doctors believe IDV may be easier to take if it is given with RTV. Patients who take IDV and RTV together may be able to take IDV only twice a day and at a lower dose. This study will gather information about the safety and side effects of using IDV and RTV together.