The FreeBusy solution helps you organise and schedule meetings much easier, because you can see when invited employee or friend are already busy with other meetings and when they have free time slots.
It is a (less known) world standard, so it is supported by many mail clients and calendars (including Microsoft Outlook and Mozilla Thunderbird). And, in addition, it is secure, because only time frame and no other details are published and shared with other parties.
To use this solution, you need a mail client or calendar that supports FreeBusy solution either directly or through some kind of plugin. All that is needed to start using FreeBusy is around 5-10 minutes for initial configuration. Once correctly configured, you need to do nothing else. Your time slots are automatically exported to FTP server and free/busy slots for other employees are automatically read from FTP server.