As the reliance of communities on critical cyber infrastructures is growing, they are becoming more vulnerable to cyber attacks. The Community Cyber Security Maturity Model (CCSMM) was proposed to help communities establish viable and sustainable cyber security programs. Information Sharing is an important part of the CCSMM but there are significant aspects to be explored. Collaborative information sharing helps a community detect potential risks and prevent cyber attacks at an early stage. It also facilitates incident response as well as preparedness activities in communities. In this paper we discuss the necessity of information sharing and provide guidance on the types of information needing to be shared. We define threat alert levels of community cyber security and discuss how different levels affect information sharing. We propose a collaborative information sharing framework that aims to improve community cyber security. Finally, we discuss practical issues and areas for further research.