Get yourself a SkypeIn number. Or two.
408 and 415 probably don't mean much to you if you don't live in the Bay Area but they're two of the most important local area codes. Moral: get a local phone number and you appear local (and that's a good thing.)
Start saving for the move
'cause you're going to need it. As of today, I have yet to have spoken with a company that was willing to internationally relocate me, which leads me to the next tip...
Start applying a year before you go
Ok, maybe a year's a bit much, but three months won't hurt.
Show up to the interview with jetlag
I arrived in SF at 6:40 PM one night and had a six hour interview with 6 different people the next day. I'm not talking fluffy stuff either; they threw me some hardcore CS problems and I had to dust the mental cobwebs off to recall topics I haven't touched in several years. Better believe I was hurting at a couple of points during the day. Four coffees helped. The following morning, they offered. Worked for me, it'll work for you ;-)
Practice, practice, practice
In the last year, I've had no less than 20 phone screens (most of which while I was in Austria,) 10 phone interviews, and four four-hour or longer in-person interviews. That made a difference in being polished for when the right time and the right opportunity came along.
Find temporary living
It helps if you have awesome relatives who are willing to let you stay with him when you arrive and are looking for an apartment. Alternatively, do a search for "short term furnished rentals." I liked Gaylord Suites: a bit close to the 'loin but that just makes it all the more interesting.
Go to Iran
That's right; the fastest way to San Francisco from Vienna is through... Iran! Alright, I'm not being serious but in general, I think you should go if you get the chance. It's a beautiful, amazing, and perplexing country; don't believe the hype.
(This advice is provided as-is without warranty. It may not be applicable in your situation. If it isn't, I take no blame. If it is, I'll take all the credit.)