I stumbled on this thread while searching for a solution to the same problem (batch convert EPS to JPG).
Luckily, there is now a fantastic little freeware program called Dragoman that does this exact job perfectly. You can convert from a number of formats (including EPS, PSD, PDF, etc) to a whole bunch of formats. It can do batch conversions just fine.
You can download it here:
http://creativebe.com/dragoman/
It does require Leopard or Snow Leopard.