I'd like to switch to Open Office, from MS Office, but need to know whether Calc has the same pivot table features as Excel.
Yes, it has. Calc's equivalent to Excel's pivottable is called datapilot.
As a general rule of thumb, Calc will read Excel's piovttable, and you can continue working with it. They are very similar, so if you know and understand pivottables, you will have no trouble understanding datapilots.
(One small difference is that in Excel you can right-click anywhere in the table to refresh it, in Calc you need to right-click the data-field to refresh it.)
You can read more about DataPilot here.