Shared hosting it a big pain in my A**,
I've been trying (unsuccessfully) to upload an WCF service to my GoDaddy hosting account,

At first i've got good old:
500 - Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed.

this error usally hide another a site exception that can be revealed by adding:
<httpErrors errorMode="Detailed"/> under <system.webServer>
after dealing with that i've discovered the real error is due to duplicated web.config keys with GoDaddy's machine.config
the keys are

<modules>
      <add name="ScriptModule" preCondition="integratedMode" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</modules>
<handlers>
      <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</handlers>

That was solved by removing GoDaddy's key with pre-remove tags for each add tag like so:

<modules>
      <remove name="ScriptModule"/>
      <add name="ScriptModule" preCondition="integratedMode" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</modules>
<handlers>
      <remove name="ScriptHandlerFactory"/>
      <remove name="ScriptHandlerFactoryAppServices"/>
      <remove name="ScriptResource"/>
      <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</handlers>

after that issue, I discovered that Godaddy doesn't recognize WCF service extension (.svc) and i'm getting the following error:

There is no build provider registered for the extension '.svc'. You can register one in the <compilation><buildProviders> section in machine.config or web.config. Make sure is has a BuildProviderAppliesToAttribute attribute which includes the value 'Web' or 'All'.

so to solve that i tried adding the extension my selfe by adding the following in the web.config under <system.web>:

<compilation>
      <buildProviders>
        <add extension=".svc" type="System.ServiceModel.Activation.ServiceBuildProvider,
         System.ServiceModel, Version=3.0.0.0, Culture=neutral,
         PublicKeyToken=b77a5c561934e089"/>
      </buildProviders>
</compilation>

only that took me back to 500 error,
I finally broke down and (no I did not cry) contact My beloved hosting company only to find out that they do not support WebServices.

If for any reason this post came up on your search and you're at step one...
walk it off - there isn't any known way of making WCF work on Godaddy Hosting account,
I've spent 4 hours learning it the hard way :(