you wont be able to play directly from the last.fm site...
they are working on an app (it was even in BB App World for a day, but it got pulled for some reason)
I had a bit of a back-and-forth with the dev on twitter (Sam Steele (c99koder) on Twitter
) a few weeks ago, but the app hasn't re-appeared :(
at least in the US i get to use Pandora and Slacker