Sharing files from Lion to Windows 7

I'm using an Airport Extreme, wired to the Lion machine, wireless to Windows 7 (a guest network, but have tried it on the normal network).

I can't seem to get the computers to connect. The Windows machine said it could see the Lion machine but it wouldn't respond. I think I have all the normal sharing settings prepared, same workgroup and all.

Is it possible with wired/wireless connections?