To gain an understanding of the differences in microevolution and macroevolution, you will need to read the following pages on the Berkeley Evolution 101 site:

• Microevolution 
• Defining microevolution
• Detecting microevolutionary change
• Mechanisms of microevolution
• Macroevolution
• What is macroevolution
• Patterns in macroevolution

The Brightstorm video, Microevolution - Macroevolution, gives a good basic explanation of the differences.