I just installed Apple's Leopard 10.5.2 and it finally fixed my Windows networking issues!
Prior to installing this release, from a Windows PC, I could not longer view my Apple Mac computers when I clicked View workgroup computers. After installing Apple OS X 10.5.2 (Leopard) I can now view them. Using Leopard, I never had a problem viewing any Windows PCs from my iMac or MacBook, but I was unable to find a work-around for this issue. Finally, Apple has fixed the problem!