The WPEC Bulk Tools plugin has just been updated to version 0.0.3. The update (inc the 0.0.2 update) provide support for newer versions of WordPress and the WP eCommerce plugin as well as a new bulk file upload feature to set prices from a CSV file.
The WPEC Bulk Tools plugin can be downloaded free from the official WordPress plugin directory.
The latest update has come about following a brief email chat with one of the existing users. Thanks to r3altordotcom on twitter.