I'll just reiterate what other people have posted in saying that any "offer" of unlimited bandwidth is dodgy to say the least. It means that they are overselling their server space and bandwidth and also if you use "excessive" amounts of bandwidth and space they will simply kick you off.

It is only an advertising ploy - if people do take advantage then they are likely to remove you from their servers.

I'd advise finding a more reputable and well known host.