Intruder? Has my computer been broken into?

first of all do a virus scan then use a spyware/malware scanner and see if there are any viruses or spyware. I would also recommend using an anti-ketlogger program such as Ihate keyloggers. it's a free demo

When Itunes is connected through a network it searches for other people who have Itunes open on the network. If it finds another Itunes program open on a network than it allows that person to connect to other peoples music libraries and listen to their music. You can have this not happen to you by turning sharing off. You haven't been hacked it's just that someone connected to your Itunes Library.

No, it's not a virus, actually with iTunes if you're on a network you can share music. I'm on a college campus and since I'm on a network and connected to other computers I can share and listen to music from other people using iTunes.

Since your firewall was probably your only method of protection, they did not actually have to "hack" into your system. Instead, your computer was probably dealt with normally by the hotel LAN system and all of your resources (files) were made public.

If your system is working normally and you haven't found anything other than the extra file, you are probably OK. Just remember to use your firewall next time.