Use a style sheet.
Do something like
INPUT { background-color: #000000;}
and that should change all your INPUT tags.
If you want to extend it for only a certain ones, append a class name to it.
ex
INPUT.myClass {background-color: #000000}
then all the INPUT tags belonging to class myClass will be affected.
I know this works for MSIE, I don't think it works for NN 4.x
good luck