I'm running a fedora distro on VMWare in my XP machine. My XP machine is connected to a windows network. How can I detect my linux machine in this network ?
This is the wrong way to go about it. First install Fedora, and then use VMWare for your WinXP ;)
But on a serious note - it is important to check if you are using bridging for your network access. This means that from the network side of your machine you should be able to see both machines on the network, with different IP addresses.
Have a look at each machine's IP, and check if you can ping it from a network machine. Each of the machines are supposed to be uniquely identified. You can also test this, by making a windows network neighborhoud (NetBIOS) connection to the machines from the network side.
If you can ping both ip's, and can make a NetBIOS connection to only one you only need to install and configure Samba on the Linux machine. If on the other hand you can ping both IPs, and make a NetBIOS connection to both, but the NetBIOS connection is the same on both IP's - you will have to reconfigure your VM guest to make use of bridging, and not just NAT.
This is a simplified (and somewhat incorrect on some unimportant technical points) comment on your problem, but should point you in the right direction.
You might want to look at Virtualbox as a VMWare alternative - I've heard good things about it.