This study evaluates the safety and efficacy of plerixafor given in addition to granulocyte-colony stimulating factor (G-CSF) for collection of peripheral blood stem cells (PBSCs) for autologous transplantation in patients with non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM). Efficacy outcomes include evaluation of fold increase in circulating CD34+ cells from just before the first plerixafor injection to 10-11 hours post plerixafor (just before apheresis) and assessment of successful polymorphonuclear leukocyte (PMN) engraftment after transplantation. Data from this protocol will assist in the determination of the dosing schedule for future studies.