Need my website to talk to my Amazon account, XML...whatever

I am a pro merchant at Amazon that uses their "flat file" data feed system for selling my products online. It is too difficult and time consuming to admin it. I am constantly making changes to my website, and I don't want to use 2 admins to make changes so that they also show up on Amazon. I only want to make the changes/additions in my website admin, and then send the changes over to Amazon. This can be in an xml file or any other preferred way that Amazon may need the information. All of the information in the flat file: classification, keywords, etc... would have to be maintained on the Amazon site. Any new items added in my website admin would need to have these same Amazon provided attributes and keywords etc.. Please bid on this if only if you are familiar with this type of work.