The Gantt template is in .xls format, which works in most spreadsheet software, not just Excel, and it's a free download from Dave. Manual Gantt Charting in Excel [David Seah] ...

Here’s how to make a Gantt chart in Excel to accommodate complex agile project management within the familiar tool.

Software engineer Chandoo shares some Excel conditional formatting tricks that make for good-looking and useful spreadsheets, like a Gantt chart.