Network Issue with Leopard

Hi,

I have an 20" iMac and a MacBook and I've installed Leopard on both in the same way. The main problem I'm having is that in Finder on the iMac I can see both my MacBook and Windows Laptop and can access files on them no problem. But in my MacBook's finder, it either takes ages to access the iMac and Windows Laptop or else it doesn't show any files on them at all. Is this just an issue with MacBooks then and has anyone found a way around it?

Cheers!