Microsoft Office Visio is a software to draw flowchart, plan diagrams, electric diagrams, chart, process, layout, class and network diagram, etc. This is perfect software to create and save diagrams to represent your project planning and thought. As a part of ms office, it is not free to use it. You need to spend hundreds to get the commercial Microsoft Office Visio. If you want to save your money, you can
download free Microsoft Office Visio alternative software. There is one freeware Visio software that has basic ability similar to Ms Visio, it is Dia software. Dia was developed by Gnome.org and it provides more than enough tools to draw diagrams. Basics diagram components are available, such as boxes, ellipses, polygons, and sticky connecting lines and arrows. The best feature is its ability to crate layers, thus you can create diagram and sub-diagram (as a part of main diagram). It is totally free and legal to
free download Microsoft Office Visio, download Dia software :D
Dia software download link for free Download Microsoft Visio alternative:
http://live.gnome.org/Dia/Download
There is also a web-based online software as an alternative for Microsoft Office Visio, it is Gliffy. You can use it for free as long as you have an internet connection :D
Gliffy, Web Based Visio Software : http://www.gliffy.com/