(Note I've interviewed for multiple jobs at Blizzard, this is sort of a combination of them all)
Fairly basic process consisting of initial phone screen, detailed phone screen, skype interview and/or onsite visit. Nothing out of the ordinary here compared to other companies with "direct-hire" opportunities.
However, be prepared for a gap of about 2 weeks if not longer between steps. If there is a major company event (Blizzcon, Product launch, etc.) expect that it will take at least an extra week or two. If something has to be rescheduled, it will be rescheduled for about 2 weeks later. I got the feeling that if I had not reminded them, they would have totally forgot about me.
The offer that was eventually extended was good but not great. I declined it for two reasons:
1) Salary - The salary was good but ~25% of it was wrapped up in bonuses that pay out in annual/semi-annual frequencies.
2) Time - Because they took so long to get me an offer, I had already accepted another offer.
Salary was not talked about until the very last phase of the process, which I find odd. We could have maybe saved each other time and money if it was done earlier in the process. The time was so bad that my "last" interview with Blizzard was the same week as my "first" interview with the job I ended up taking instead.