I wrote an article earlier that said the strike may have been averted, because the studios may give one of the big items the WGA wants. (More residuals and profits.) Of course, it all comes down to bargaining, but why did the WGA still go ahead and vote to approve a strike (90% of members voted yes)?
Again, leverage. If studios think a strike could happen, not only will movies be hurt, but television shows especially, which require scripts written by Guild members (reality TV doesn't count).
I think the studios may accept more of the WGA's terms if they fear a strike could happen, which would deal a blow to TV and film production. I don't want to think of what would happen in a matter of months (if not weeks) to my favorite shows like Heroes and 24. Same with the shows you all love and watch. Not to mention movies going into production; there's a real possibility Transformers 2 and G.I. Joe may not hit the cameras if scripts aren't fully ready to go. (Then again, some may argue for that!)
More details as they come in.
Source: Yahoo! (and AP)
A good read is Deadline Hollywood Daily's analysis, which I think covers quite a bit of the story.