Hi
eBay offers a set of powerful tools to enable people running their own websites to integrated their live eBay listings with their website
This is done with the use of APIs (Application Program Interface). Conceptually, APIs are like functions that the eBay platform exposes that enables 3rd parties to replicate most of the functionality that the eBay platform performs
You can find more information about eBay APIs at
http://developer.ebay.com
Your need will be served with the use of the GetSearchResults API. This enables you to pass search keyword queries with all the typical filters that are available in search (including your username - to display only items being sold by you). The search results are returned as an XML which would make it easy for you to parse the data and present it in a manner that suits you on your website
The documentation is available here :
http://developer.ebay.com/DevZone/XML/docs/WebHelp/index.htm and here :
http://developer.ebay.com/DevZone/XML/docs/Reference/eBay/io_GetSearchResults.html
You will have to code this using a supported programming language (eBay supports all popular languages such as PHP, ASP, Java, Perl VB6 etc). The developer.ebay.com site has all the documentation you required along with code samples
You will have to sign-up for the developer program and procure your keys to make the API call programmatically
Get started with eBay APIs here :
http://developer.ebay.com/quickstartguide
Trust this would be useful for you. Please post again in this thread if you have any queries. Alternatively, we also have a Developer Support board here :
http://developer.ebay.com/community/forums/