According to the announcement on the Google Reader blog it should be avaiable for phones running donut (Android 1.6) and above, so you're covered for that.
The blog doesn't mention any geographical restrictions and I'm in Europe (UK) and I've got it, so it's definitely available outside the US.
If you've got a barcode reader, then you can just point your phone at the QR barcode on the blog and it should take you straight to the Market page for the app (if it is in your Market).
According to Reader's Androlib page, it's currently available in the US, French, Spanish, Italian, German, Dutch, Japanese, Swiss and Russion markets.
There are ways to change the settings on your device so that it looks at the US (or another region's) Market, see this previous question for more How do I use the US Android Market.