Nothing like an answer nearly 5 years after the fact, but here's my couple of shiny pennies worth.
I'm currently building something that would do the job just nicely... https://blinked.in - what is fast becoming the largest UPC / EAN13 barcode database (we've added over 7M barcodes in the last week alone), whilst we're still in the alpha stage of development we're introducing a very straightforward, low cost API to provide just this sort of data access.
We've only been in dev for a couple of months, but already have a stable web platform, rapidly expanding database and desire to keep things simple.
Hope this helps you, or some future reader, in some way.
Updated
Our API is now live - https://blinked.in/api - and we've thrown in a 100 free calls per day, and you can earn credit from helping us discover new barcodes - https://blinked.in/bandwidthaccount
