I figured out How to Add A Gantt Chart to Sharepoint 2010 Foundation last year, but I forgot and it took me over an hour to figure it out again, so this time I am writing the process down. There are two ready ways to create a Gantt chart via the GUI:
Create a Gantt from New List:
The nut of the problem is that Microsoft calls this webpart a PROJECT TASK.
- Click SITE ACTIONS (at top left of sharepoint window)
- click MORE OPTIONS
- scroll down and click on PROJECT TASKS
“…Project tasks lists provide a Gantt Chart view and can be openned by Microsoft Project or other compatible programs…”
Convert an Existing List to a Gantt Chart
- Go to your list
- Click the twisty from the the bread crumbs (at the top of the page)
- Select CREATE VIEW
- Select Gantt View
You will likely find THIS help article from Microsoft to be useful.