Is it possible to print multiple worksheets in a single Excel workbook to a single .PDF file?

Select the worksheets that you want to print by holding down the "shift" or "control" key while clicking on the sheet tab.  Select the "Print..." command from the "File" menu and make sure "Active sheet(s)" is enabled in the Excel print dialog.  More information on selecting multiple worksheets is available at:

http://office.microsoft.com/en-us/assistance/HP052024921033.aspx

Alternatively, if you select "print to file" from the Excel print dialog all worksheets will be created in a single PDF file.