I have an Aerial layer (.SID file) which I would like to re-project in QGIS, then I would like to open it in ArcEngine. I've figured out how to do this with vector layers in GGIS, its just a right click, "Save As", but my Aerial layer does not have a "Save As" option.
If you are looking to reproject an aerial image in QGIS you will need to make sure you have the GDAL Tools plugin installed (which you can find in the Plugin Manager). When it is installed you will see the Raster Tab in the main frame. In the Raster tab you will see Projects. If you aerial has an existing projection, use the GDALWARP (Reprojection) tool. If there is not an existing projection, you can use the Assign Projection tool.