It depends.
If you want to do and erase & install, which won't preserve any of your information, then no because the installation will erase everything on the hard drive and start over.
If you want to do an archive & install, which would preserve your user information, then you'll still need the password to do any software updates, but you won't need it for the installer itself.
If you have a firmware password, you'd need to reset that before installing because it will give you a password prompt before allowing you to boot from the install CD. If you don't see that when holding C to boot from the CD drive, you don't have a firmware password. If you do, just take out one memory module, reset the PRAM, and it'll disappear.
All of this is nullified by the fact that the OS X install discs have all contained a reset password utility since the beginning. It'll be in the Utilities menu if the disc has 10.3.9 or higher, or in the Installer menu if it's a lower version. The steps to reset it can be found
here.