Tcpdump Installation

[JosephMu]

Hi, everybody.
I'm a newbie to Linux and i m trying to install tcpdump .
i ve already logged in as root and download the latest version of it.

tcpdump-4.0.0.tar.gz

but when i run:

yum install tcpdump

it doing nothing and says that i have install the

tcpdump-3.9.8-4.fc9.i386

Loaded plugins: refresh-packagekit
updates-newkey                                           | 2.3 kB     00:00    
fedora                                                   | 2.4 kB     00:00    
adobe-linux-i386                                         |  951 B     00:00    
updates                                                  | 2.6 kB     00:00    
Setting up Install Process
Parsing package install arguments
Package 14:tcpdump-3.9.8-4.fc9.i386 already installed and latest version
Nothing to do

could anyone help??
I'm a newbie and all kinds of silly mistakes could be possible.
thanks

[JosephMu]

BTW,
is the tcpdump a widely used internet packets sniffer software or not?
are there any better softwares?

do i have to download and install
tcpdump-workers.asc ??

[root@localhost ~]# locate tcpdump
/usr/sbin/tcpdump
/usr/share/doc/tcpdump-3.9.8
/usr/share/doc/tcpdump-3.9.8/CHANGES
/usr/share/doc/tcpdump-3.9.8/CREDITS
/usr/share/doc/tcpdump-3.9.8/LICENSE
/usr/share/doc/tcpdump-3.9.8/README
/usr/share/man/man8/tcpdump.8.gz

thanks