Accessing Shares Across W2K/XP

my network consists of 2 workstations with W2K and a laptop with windows XP Professional. the W2K systems can see each other fine, but the laptop doesnt see either of them. I have got internet access running to all systems (even the XP) but i havent been able to see other computers from the laptop. the laptop is running on the network via a wireless router if that will help (the W2K systems are wired 10/100).