Mass SSH Key creation

Is there an easy to use tool to create a large batch of ssh key's at one time?  I want the developers/designers in the company to only use sftp/ssh instead of ftp or having an accounts password, so the idea was to issue a 1024 or 2048 rsa key to everyone, with a keyphrase chosen by them.  I've already got scripts in place to automagiclly append new keys to authorized_keys from windows... just need to make about 15-17 keys.