Works fine for me
I installed RC1 over beta 6, rebooted the hardware, installed Parallels tools, restarted the guest, and network access (via Airport) works just fine. Printing to network printers works fine.
It's critical to reboot the hardware (OSX) after installing a new version of Parallels to get the new kernel extensions loaded though. In the Mac world, installing an app is usually just a matter of dragging it to a convenient place and starting it, but Parallels isn't just a Mac app, it's part of the operating system, and like some of the apple hot fixes, requires a hardware restart to fully install.
Not restarting the hardware and starting Parallels can (and has for me) leave an unstable system. Restarting the hardware fixes the problem.
I'd suggest to the Parallels team that they require a restart afer install just as Apple does when they replace an OS chunk.