I already mentioned previously that SQLite will be supported on WinRT, provided an excellent choice for storage needs if those involve a need for relational database engine. Tim Heuer blogged about how to compile SQLite source code, which is a bit of a chore. Luckily you can now download precompiled binaries for both 64 and 32 bit Metro Style applications here. Of course, SQLite .NET ORM project is keeping with changes as well as Tim shows in his video, updating their source code to be compliant with WinRT. You can add this NuGet package to your metro style application via NuGet, eliminating the need for all the manual steps.
Enjoy the coding!