Before I could get started on LinqtoCRM, I had to get Visual Studio 2008/WCF and CRM to agree on a common mode of interaction. I must confess that, in the past, I’ve only picked up just enough web services knowledge to get things humming (which was almost nothing in VS 2003/2005). WCF, with its notions of “endpoints” and other newfangled stuff, seems a bit more configuration heavy. Here’s what I did to get it to work. In “app.config”, you need this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="CrmServiceSoap" closeTimeout="00:01:00" openTimeout="00:01:00"
        receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false"
        bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
        maxBufferSize="100000000" maxBufferPoolSize="100000000" maxReceivedMessageSize="100000000"
        messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
        useDefaultWebProxy="true">
          <readerQuotas maxDepth="32" maxStringContentLength="100000000" maxArrayLength="100000000"
          maxBytesPerRead="4096" maxNameTableCharCount="100000000" />
          <security mode="TransportCredentialOnly">
            <transport clientCredentialType="Windows" />
          </security>
        </binding>
      </basicHttpBinding>
    </bindings>
    <client>
      <endpoint address="http://foo/MSCRMServices/2006/CrmService.asmx"
      binding="basicHttpBinding" bindingConfiguration="CrmServiceSoap"
      contract="ServiceReference.CrmServiceSoap" name="CrmServiceSoap" />
    </client>
  </system.serviceModel>
</configuration>

And in code, do something like this:

CrmServiceSoapClient client = new CrmServiceSoapClient();
client.ClientCredentials.Windows.ClientCredential.Domain = "foo";
client.ClientCredentials.Windows.ClientCredential.UserName = "bar";
client.ClientCredentials.Windows.ClientCredential.Password = "foo";
client.ClientCredentials.Windows.AllowedImpersonationLevel =
	System.Security.Principal.TokenImpersonationLevel.Impersonation;

Addendum: I just noticed that Visual Studio still lets you create a traditional web reference (as opposed to a service reference). This may be a lower friction approach: