A simple explanation of interlacing and fields here

[Graham Meredith]

I know this has often been explained on this forum before, but for dummies like me, some times I have come away from reading them with a hurting head

I accidently stumbled across this Adobe Premiere help page, which I think has been the easiest (for me, anyway) explanation I have seen so far:

http://www.adobe.com/support/techguides/premiere/prmr_interlace/main.html

Graham