Hey, after I had restarted the mac I saw it in network on my pc. When I clicked on the mac network it asked me for a network user name and password. Silly me, I kept typing the pc info for this when I should have been typing in the mac info. After that I had no problems sharing files.
My other concern now is formatting an external hard drive so it could be plugged in either to the mac or pc without having to reformat again. I don't think the free-NTFS software is available for OS X Lion yet.