 Patients in this study will take telbivudine for 24 weeks. At Week 24, patients will add a HAART regimen containing lamivudine and efavirenz plus either didanosine or abacavir. Patients who are unable to add a HAART regimen at Week 24 due to lab abnormalities or other contraindications will be allowed to delay the initiation of HAART until Week 30. Patients may initiate HAART prior to Week 24 if deemed medically necessary by the primary HIV care provider. Patients will take both telbivudine and HAART for 24 weeks. At Week 48, patients will discontinue telbivudine and continue on the HAART regimen alone for an additional 12 weeks. 