In Geostationary Orbit
Read this MacOSXHint on how to reset your 10.5 password via the single user mode.
1. Boot into single user mode (press Command-S at power on)
2. Type fsck -fy
3. Type mount -uw /
4. Type launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
5. Type dscl . -passwd /Users/username password, replacing username with the targeted user and password with the desired password.
This allows you to reset the password in single user mode without booting from the install media.