Den Delimarsky explains how to apply pseudo-paged navigation in a list on Windows Phone 7.
Source: DZone
There are several ways content can be browsed inside a list on Windows Phone. Most of the current applications (like Facebook) are using the "Load More" method - by modifying the default ItemPresenter it is possible to add an extra Button control at the end that will trigger the list update (for the list that is currently bound). This is a pretty decent method to split a large collection in smaller chunks and then access it that way. However, the situation becomes a bit more complicated when the items are already loaded and all that needs to be done is navigate through the existing set.