One interesting question from the WCF forums: how to enable the cross-domain calls to self-hosted services, if there isn't an "easy" place to put the clientaccesspolicy.xml (or crossdomain.xml) as there is on IIS? The post at http://blogs.msdn.com/carlosfigueira/archive/2008/03/07/enabling-cross-domain-calls-for-silverlight-apps-on-self-hosted-web-services.aspx explains how to use the web programming model capabilities of WCF (.NetFX 3.5) to do that.

Carlos Figueira
Software Design Engineer in Test
Connected Framework Team