How to "paste-over" a line with Vi(m)?

I want to change the copyright line of the source files of a project to have a copyright of "2007-2008" instead of just "2007". I know that I can yank one changed line ("yy") and paste it ("p"), but I'm wondering if there's a way to delete a line without yanking it (which is what "dd" does automatically) so I can quickly replace the old lines with the new one.

>>13
Yes. I wasn't about to look up Vim's syntax for it though.