"Digital Repositories offer a convenient infrastructure through which to store, manage, re-use and curate digital materials. They are used by a variety of communities, may carry out many different functions, and can take many forms. Digital repositories are also commonly referred to as institutional repositories or digital archives" (Semple, 2006, para. 1).
The most common location for any OER to be found is in a digital repository hosted by an institution (such as a consortium or a university). Repository systems are designed with open access in mind, and you can deposit your OER in them with the expectation that they'll be findable and accessible to everyone. Many of the places you can find OER are the same places you can share yours.