Hi,
This sounds straightforward. I imagine you'll want to regenerate the CSV file on an ongoing basis if your supplier sends you replacement XML files? If so I can provide you with a little program to do the conversion whenever you want. This will be able to be run on any up-to-date Windows machine.
If you can share a sample of what the XML file looks like, that would be great. This is just to confirm it has all the information we'd need to put into Magento. I believe there is a fairly standard CSV format for importing into Magento, but if you have any information provided (I think you can do a CSV export of products from Magento - even if your database is empty that will give us the format it needs) that would be useful also.
I won't ask for any payment until I've provided you the software and you're happy it works for you.
Regards
Chris
PulseLab Ltd (UK)