Authenticating and authorizing users on MVC and WCF
<system.serviceModel>
<behaviors>
  <serviceBehaviors>
    <behavior name="MyCompany.Api.Services.WebService.MyProductServiceBehavior">
      <serviceCredentials>
        <userNameAuthentication
        userNamePasswordValidationMode="MembershipProvider"
        membershipProviderName="MyCompanyMembershipProvider" />
      </serviceCredentials>
      <serviceAuthorization principalPermissionMode='UseAspNetRoles' roleProviderName='MyCompanyRoleProvider' />
    </behavior>
  </serviceBehaviors>
</behaviors>
<bindings>
  <basicHttpBinding>
    <binding name="MembershipBinding">
      <security mode="TransportWithMessageCredential">
        <transport clientCredentialType="None" />
        <message clientCredentialType="UserName" />
      </security>
    </binding>
  </basicHttpBinding>
</bindings>
<services>
  <service behaviorConfiguration="MyCompany.Api.Services.WebService.MyProductServiceBehavior" name="MyCompany.Api.Services.WebService.MyProductService">
    <endpoint address="" binding="basicHttpBinding"  bindingConfiguration="MembershipBinding" contract="MyCompany.Api.Services.WebService.IMyProductService" />
  </service>
</services>

api = new MyProxyService.MyProxyServiceClient();

        api.ClientCredentials.UserName.UserName = userAcct;
        api.ClientCredentials.UserName.Password = password;

        api.MethodCall();