On December 23rd Real Madrid left the Nou Camp with a 1-0 win and left a Barcelona side in shambles, including losing Ronaldinho for a weeks.  Real Madrid were anointed champions and you couldn't blame anyone for the premature king-making.  Barcelona was plagued with injuries and fell as far back as 9 points.  All this changed within a week.  Thanks to a controversial win at Zaragoza it looks like Barcelona have found their footing and have put Madrid on their back foot.  

The two teams have gone in different directions since that match, just not how you may think.  Madrid had eyes on the treble, but now are out of the Copa Del Rey, down 2-1 in the Champions League, and have seen their hold on La Liga shrink to 2 points.  Barcelona are in the Copa semis, won 3-2 away in Champions League, and are only 2 points back.

Biggest factor in all this: Injuries.  Barcelona are getting healthy, while Real seems to be getting knocked down one by one.

Here is a more in-depth look:

http://blaugranafutbol.com/story/2008/2/24/171412/812