ebay competitor analysis

im looking for a small script / program that can show me what my competitors are doing on ebay. i want to see how many items they are listing on a daily basis and how many they are selling with conversion ratios if possible. the script must be in php and if it uses a database (ill accept a script that does it on the fly if you like) then it must be mysql. we currently use oscommerce as a selling site other than ebay so ill probably be running it from there (although integration is not essential). ebay lets anyone (not logged in) see what other sellers are selling (i think) but they must be logged in to view completed items (again, im assuming here). the way i would do it is send an http request through php using a properly formed url and GET string to ebay and parse the results into a database then query it as necessary. the completed listings bit will be a little harder as you need to be logged in to do it but im sure that will be fine as you can easily pass usernames and passwords using php. alternatively you can make use of the ebay developers zone where it provides a number of code examples to use to get to the same information a little easier. we need this software quickly but all timescales will be reviewed. please pm if you need any more information thanks