Agree with the previous posters. The IFR charts are in SD, but you'll need to set the filtering correctly.
To add any other stuff (e.g. checklists), copy them to the mobile device using your favorite app (GoodReader works for me), select the document and say "Open In...". SD will be in the list if the file type is document/pdf, and possibly a few other formats as well.
Those documents will show up in your SD Document Browser as well. Although they're in a separate section, and I don't know if its possible to associate them with an airfield, for instance.