Oracle Database Discussions

Guys,

I have two qs.

1) How to change the listener port no from 1521 to some other value?
I did change the value in listener.ora and restarted all the oracle services. but
when I try connecting to the DB it says ' ORA-12154: TNS:could not resolve the connect identifier specified '.
2)What is the procedure to create multiple listeners on the same instance?
Can I have something like the one below in my listener.ora file?

SID_LIST_LISTENER1 =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = D:\oracle\product\10.1.0\db_1)
(PROGRAM = extproc)
)
)

LISTENER1 =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
)
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = *.*.*.*)(PORT = 1521))
)
)
)

SID_LIST_LISTENER2 =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = D:\oracle\product\10.1.0\db_1)
(PROGRAM = extproc)
)
)

LISTENER2 =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
)
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = *.*.*.*)(PORT = 1601))
)
)
)

Please let me know.

Many Thanks in Advance

Shyam.