First off you need to turn on file sharing in windows.
Open your control panels folder in the start menu, in the left pane choose classic view. Then open "Network Connections". In the left pane select "set up a home or small office network".
Using the "Network Setup Wizard"
This program may ask for a network port if ran for the first time, just select the right one. Windows may need to be restarted afterwards.
1. For "select connection method", choose "This computer connects through a residential gateway or through another computer on this network".
2. For "Give this computer a description and name", choose something you like this will be its name on the network.
3. For name your network. I think the default in OS X is "WORKGROUP" these names must match.
4. File and printer Sharing, select "turn on file and printer sharing"
5. Click next on ready to apply settings
6. For you're almost done, select "Just finish the wizard; I don't need to run the wizard on other computers.
7. Click finish
Now to make your hard drive available. Open "My Computer" right click on the hard drive you want to share and select "Sharing and Security".
1. Under the sharing tab click the text that states "If you understand the risks
but still want to share the root of the drive, click here".
2. Under the sharing tab, in the "Network sharing and security" box tick the boxes for "Share this folder on the network" and "allow network users to change my file" you can also set a "Share name" for this volume.
3. select "OK" or "apply"
Now the volume should be available for network users.
To connect to the Windows shared volume from your Mac.
http://tech.yahoo.com/gd/logging-into-a-windows-pc-from-a-mac-and-vice-versa-/200481
If you are running a third party firewall in your PC you will need to specify the IP address of your router and a small IP range of your networks computers in it as a trusted zone. So that the firewall will allow connections.
If you are not running a firewall I would recommend downloading the basic free edition of "
Zonealarm" it does wonder for your PC's safety. They also have a pay version "Zonealarm Pro" but this is only needed if you need to use your PC as a network bridge or if it is acting as a router with windows "Internet Connection Sharing"
You can also file share to the windows computer from your Mac.
1. Open system preferences
2. Click on sharing
3. In "Services" tick the "Windows Sharing" box
4. Click "Firewall" tab and make sure the firewall "windows sharing" box is checked.
5. quit system preferences
To check or change the network name in Mac OS X
http://docs.info.apple.com/article.html?path=Mac/10.4/en/mh1165.html
Edit: I forgot to mention this but you should set up a static IP address in your router for your Mac and PC. Check your manual on how to do so. I found this makes the sharing experience more reliable.
what a comprehensive answer. Thank you very much!