If you have a Nikon camera and it saves in the NEF format on the camera, you can transfer the NEF to your hard drive via ViewNX 2 as a NEF. Then with Corel PaintShop Pro X4 Ultimate can view the NEF from your hard drive. If you modify the NEF in Paintshop then you have to save as jpeg. I haven't been able to modify my NEF's and save them as NEF, if anyone knows how to...please share!!
You can save NEF's as JPEG's by doing File...Save As when you have the picture selected.