Nikon Lens Compatibility Chart - Plus: Depending what cameras and lenses you have - or want to have - these charts may be useful.
Amazon.com: EN-EL9 EN EL9a Battery Charger Pack, LP Charger Pack Compatible with Nikon D40, D40X, D60, D3000, D5000 Cameras, Replacement for Nikon EN EL9, EN-EL9a & MH-23 : Electronics
What lenses can I use with the D100 or D70?
Amazon.com: EN-EL9 EN EL9a Battery Charger Pack, LP Charger Pack Compatible with Nikon D40, D40X, D60, D3000, D5000 Cameras, Replacement for Nikon EN EL9, EN-EL9a & MH-23 : Electronics
Nikon Camera and Lens Compatibility Chart
D40 | Nikon
Nikon D40 Review - Optics
Nikon System Compatibility
Amazon.com : Nikon 70-300 mm f/4-5.6G Zoom Lens with Auto Focus for Nikon DSLR Cameras (Renewed) : Electronics
Nikon Camera and Lens Compatibility Chart
Which Nikon DSLR camera can I use my old F-mount lenses? - Quora
Amazon.com : Nikon D40 6.1MP Digital SLR Camera Kit with 18-55mm f/3.5-5.6G ED II Auto Focus-S DX Zoom-Nikkor Lens : Digital Slr Camera Bundles : Electronics
Nikon System Compatibility
Review Nikon D40 | Happy
Nikon System Compatibility
Nikon D40 Manual Focus High Power 1000mm Lens - Walmart.com
Lenses for SLR and DSLR cameras - Wikipedia
Nikon Lens Compatibility Chart | PDF | Nikon | Digital Single Lens Reflex Camera