[vod[k]a]

I know that I cannot use the iTMS in Europe, but what will happen to my purchased songs when I move to Europe (next week)? I don't want them to lock up, but I've heard that this can happen. Is this true?

[wataru]

You can't authorize your computer outside of the US. If you never need to reauthorize it, then you'll be set. But if you do (in the case that iTunes loses its prefs) then you'll be screwed.

I suggest a two-pronged approach:
1) Make backups of your prefs frequently (I don't know where exactly iTunes keeps track of authorizations, so I suggest maintaining a backup of both your ~/Library and the folder containing the iTunes Music Library files)
2) Burn your purchased music to audio CD, and then rip those to MP3. You will lose some quality, but that's better than losing the songs altogether. Keep the CDs around in case you lose the MP3s.

[sandsl]

Originally posted by wataru:
[B]...then you'll be screwed.

You won't be screwed..just e-mail apple iTMS support and they'll make sure everything works.