Mac OS X joining Windows XP network help needed

I just got a new Macbook Pro, and I've got most of my network problems figured out except one: I can't get shared folders to show up on either my Mac or my PC. I can join the wireless network fine and access the internet, and I can also share my PC's Itunes library with my Mac's Itunes, yet I can't figure out how to share files between the two.

I did a little research, and it seems I have things set up correctly. My PC (running Windows XP Pro) has sharing enabled, and I have several shared drives which I can access fine with my other PC's on the network. But nothing shows up in the network portion of my Mac.

Anything I'm missing? Thanks for the help.

Jam it back in, in the dark.