Im sure that everyone outside the US is currently in the same boat, would love to play with skyfire, but is frustraited with the lack of non-US availability.
Well Im based in the UK and I just signed up with any US number, I basically got one from google.
I still recieved the email from skyfire with the 'download to pc' option, The link on that email asked me to generate a password, which i did.
I installed the cab and expected there to be an IP block or something similar for the region but surprisingly the ID email and password went through just fine.
the happy ending being that im now runing skyfire beta via the UK, bonza.
Hope this pleases a few people.