You can change the font in SQL*Plus for Windows NT/2000.
In regedit, go to
HKEY_LOCAL_MACHINE
-> SOFTWARE
-> ORACLE
-> HOME0
Create a new registry value called SQLPLUS_FONT of type REG_EXPAND_SZ and set it to your favourite fixed-width font, Eg. Courier New
Create a new registry value called SQLPLUS_FONT_SIZE of type REG_EXPAND_SZ and set it to the size you want (13 is a good size).
