How do I enable iTunes Match? I've upgraded to iTunes 10.5.1, which the release notes claim includes the widely publicized iTunes Match feature, but I can't find any way to purchase and enable it. How do I enable iTunes Match?
If you're located outside the US, iTunes Match is unavailable for the time being, due to content licensing deals.

When iTunes Match was first announced I believe Apple stated they would be working on bringing it to more countries, but these negotiations always take some time. Hard to give a definite timeframe unless Apple announces something.