http://www.nikonchat.com/18-200-nikon-vr/

Is Nikon AF-S Nikkor 18 – 200 mm f/3.5-5.6G DX ED VR compatible with the Nikon D50?
Yes – and it should work fine. (You can have some focus problems in low light at 200 mm) The DX series means it is designed to work on Nikon digital SLRs. (Lens Film work as well). The D50 VR suppports function.
nikon 18-200 vr II Lens Creep