After I posted my last blog post, Ralph Squillace responded with a link that everyone that is doing OData/WP7 development should be aware of. 2 days before I posted my Data/WP7 post, Microsoft's Mike Flasco posted this regarding the changes that are coming in the RTM version of the Windows Phone 7 library.
The current WP7 phone platform is missing some core types, types that data service client LINQ provider requires to function properly. The CTP that is currently available (and which my example was based on) has LINQ support but what Mike calls "shaky workarounds".
To address this, they are removing the LINQ translator from the data service client. There are pros and cons to this. The downside is that you will no longer be able to use LINQ based queries, but instead create your queries based on the WCF Data Service URI. The good news is that because it is beased on the WCF Data Service client that many of the features you know and love such as serialization, binding, change tracking) will be available to you.
This also means that I will be re-doing my blog post. 
Scott