Instant messaging is a popular form of communication over the Internet. Statistics show that instant messaging has overtaken email in popularity. Traditionally, instant messaging has consisted of a desktop client communicating with other clients via an instant messaging service provider. However, instant messaging solutions are starting to become available in the web browser–services like Google Talk, Live Messenger and Facebook. Despite the work done by researchers to secure instant messaging networks, little work has been done to secure instant messaging in the browser. We present secure browser-based instant messaging overlays as a means to enable convenient, secure communication in existing browser-based instant messaging interfaces. Additionally, we present a prototype implementation of the secure messaging overlays and the results of two user studies--the first study focusing on user interest in secure chat and the second being a usability study of the prototype.