The 'unlimited' just means you can push as much as you can over the 2MBIT you get with your server (cheapest packet is $89 a month with 5 servers sharing a 10 MBIT port). So in fact there is a limit to the unlimited translating roughly to about 660 GIGS a month, but if you have any questions, I suggest you contact the staff. They're very friendly and helpfull...
And don't ask me why I'm posting all these kind remarks, it's very unlike me. Maybe it's just because I've found a company I'm happy to deal with for once. Just hope it lasts for a very, very long time, but time will tell...