There are several ways to convert vcards to csv on the web – but most only do one card at a time.
I recently needed to transfer about 400 vcards into one csv file for a mail-merge – so one at a time was not too helpful!
I found this tool at http://www.inter-help.com/toolbox/aaron that will convert as many files as you want from a zip folder into a single csv.
Fantastic tool.
Enjoy!