Batch convert to PDF...how?

Mainly for Excel docs ( I need to convert many .xlxs docs to PDF to send them )

Using Office 2011.

It's very annoying to have to use the print dialogue box to save them as PDFs for each individual file ( doing around 30 at a time ).

Is there a way to do them all as once as a batch confer?

Many thanks

Thanks - seems I need to install a CUPs printer ( whatever that is! ) to use this.

Anyone know any other options?

cheers