How Could I connect a SharePoint another list which is situated in another web application? A mast get another list from another web application, and give a filter to show only this elements, which are on filter. How could I create dynamical filter ?
SharePoint exposes an API, and you can find there a service for accessing lists and the list items: ListData.svc a wcf service that follows REST protocol. Here's a link with a tutorial on how to do it: http://www.learningsharepoint.com/2010/07/09/get-list-items-in-sharepoint-2010/
If you are having trouble with the CAML query, use the CAML query builder from: http://spcamlqueryhelper.codeplex.com/
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