Password

I just recieved a MAC G4 OS 10.3.4. The original owner forgot his password and I am unable to do certain things with the MAC (like browse a windows network, etc. ).

I was wondering if you could give me a url of a program (either official or unofficial) that I can launch which will allow for me to find out the password for the default user account on this MAC. OR is there there some way to reset the password when I do not have the original password?

I am able to start the OS and do some tasks with out the password so it is not a complete brick. I am new to MAC.