yes and No.
You see with a Megaupload link your not hosting the files so your not really breaking the Law

And again it's all about where you live, Some places say Yes you can own the copy IF you have the game YET.. other places say NO!! you can't have a copy even if you Own it.
Thus why it's hard to just get a Yes/No answer about if you can or can't have/host roms.
For what i know even in the places where it's ok to have a backup it's NEVER ok to host your backups.