This study is being done to determine whether a telephone-based counseling intervention can help survivors of breast and colorectal cancer increase their weekly physical activity. Observational evidence suggests that physical activity after breast and colorectal cancer diagnosis decreases recurrence rates. Unfortunately, many people become less active during cancer therapy, and a substantial proportion never return to pre-diagnosis levels of physical activity. This study looks to see if people who have recently finished chemotherapy for breast, colon or rectal cancer can be motivated to increase their exercise by talking to an exercise specialist over the phone. The study also looks at changes in mood, fatigue, fitness, fat distribution and weight.