A new and emerging technology called femtocell brings significant improvement in terms of better indoor coverage and higher data rate. Able to be installed and maintained by individual user, femtocell provides a cost effective solution to mobile operators to achieve higher network capacity. However, interference due to two-tier network structure introduces many challenges for successful femtocell deployment. In this article, we summarize various interference and resource management techniques proposed in the context of femtocell. Specifically, we focus on interference avoidance techniques. First, the overview of femtocells, its architecture, and common issues are presented. Next, various interference avoidance techniques are reviewed. At the end, several important research directions are outlined.