"imp" command is used for the purpose in the following way:-
suppose my original acccount is "scott" and password is "12345"
Now, i want to dump the original account into a custom account named "techgeek" and password "123"

so the steps are:-

1)navigate to "run" and type there "exp"
after that a command line interface will open with the following queries:-

username: (write over here:- scott)
password: (write over here:- 12345)

Export file: EXPDAT.DMP > c:\scott.dmp


Now again, goto to the command line interface by typing "cmd" in "run"
Now, here begins the actual command:-

imp userid=techgeek/123 fromuser=scott touser=techgeek file=c:\scott.dmp

I hope i got the correct ans.

(My instincts are different from your instincts, techgeek ...pung..pam pam pam pam..sponsor of technology...:-) )