Workaround:
Go to a UK Proxy (
http://www.daveproxy.co.uk/)
Go to
Spotify has landed in the U.S. Sign up to get your invite now - Spotify (that's co.uk, Zilvia automatically pulls)
Sign up for a free account (SW3 1NF, United Kingdom)
Close proxy
Go to
Spotify has landed in the U.S. Sign up to get your invite now - Spotify
Log in
Change country
Profit.
No invite needed.
Music discovery is iffy, but still neat.