I am having the same problems with iTunes and transferring files or even accessing my Macbook pro from my iMac.
When i went to school and opened up my Macbook it recognized every other students computer (apple and microsoft).
I take my macbook home and its the same thing.
This has just recently started to be an issue as its been working fine for the past 2 years.
I have tried the homesharing iption in iTunes, turning off the firewall settings, resetting the router, going in to security and sharing settings on both devices but still nothing. It does however recognize via bluetooth.
Frustrating to say the least...
I have even went as far as going into safeboot mode and doing a diagnostic check on all of the directory settings which. came up saying that everything was running normally.
I share files pretty regularly between the two macs...this has prevented me from doing it any further.
Any KNOWN fix would help.
regards,
-glen