Short answer: No, there will not be another crash like 2008 in 2012.
Longer answer: I don’t think many intelligent people, those who actually have or manage real amounts of assets, believe in any of that Mayan Calendar hocus-pocus.
Asset values simply aren’t as inflated as they were in 2008. It’s entirely plausible we’ll see a 5% correction in the stock market at some point in 2012, and the major indexes could end the year down or flat. But the odds of another major crash are quite slim. Obviously there’s always a chance of some major, unexpected event like the Japan Tsunamis or worse, but you can’t plan for those.