We bought a baby bath with a stand on it, from K-Mart. Best invention ever, it's really saved my back. But for a while, when she was around 4 months old, Annika rejected the bathtub, so we just showered with her. You could always go with that option.

A friend of mine without a bath tub, started putting the baby bath in the shower for her little boy, and slowly transitioned him like that.