With Gantt Project you can design and build a project plan completely visually, easily and with endless possibilities within reach. For each project you can assign resources (personnel, tasks, availability of dates, calendars, holidays when the project can't advance, etc).
You can also define dependences among the different tasks that make the project, which means that a specific task can't start until one it depends on finishes. Also, all the plans and designs can be exported to a graphic format (JPG, PNG), to a PDF document or to HTML if you want to publish it on a website. If many employees or resources are used, you can assign free days in the program, both individually and generally.
Gantt Project is totally free and has a multilingual interface.