Do you ever use public Wi-Fi hotspots? If you are increasingly using them, you have company. A study done by iPass late last year, showed that work-related hotspot usage was up 68 percent in 2007, relative to 2006. Airports topped the list of public places where users wirelessly connect. The vast majority of hotspot users, though, don't take the right steps to secure their sessions. In this post, I'll cover five free open source and freeware applications you can use to lock down your sessions.