Technically speaking, users who have normal pivot table functionality in their Excel workbook can in fact use a ivot table that was created using PowerPivot. They just won't be able to view the source data in the PowerPivot window.
For example, for Excel 2010 users who don't have PowerPivot but were sent a workbook that has a PowerPivot Pivot Table, just click anywhere in the pivot table and under the 'Options' tab located in the ribbon you'll see a sub-tab 'Show'. Click on the 'Field List' button and you'll then have access to all visible measures and fields from PowerPivot.
Even better, if you want to create a new pivot table from the source data, insert a new pivot table, choose the data you want to analyse by selecting 'Use an external data source' and then click 'choose connection'. Select a connection in the workbook, which will be a data model and voilà - you have an ordinary Pivot Table sourced from PowerPivot.
Cheers,
odd_analyst