ASP.net With Sharepoint

Hi,
My client already have SharePoint portal. In MS Word there will be a option called "Other web locations" in this browse option will be there, once it is clicked dialog will open, in address bar of the dialog i paste my SharePoint  url for e.g)http:localhost this will show all files inside that. When i click any file it will ask for check-out button on top.. This is a usual behavior off office with SharePoint integration. Now the same should be moved in ASP.Net Web Forms... How to do this???