Some people seem to support Assange so much they hate Sweden. So what is really going on? There's lots of misinformation being spread. The New Statesman has a good summary of misconcetions.

Essentially, Swedish authorities want to arrest Assange to question him about a suspected case of rape. People think Assange, having been extradited to Sweden would then be extradited to the U.S. Just ask Manning how the U.S. treats people they don't like.

However, as the article makes clear, there really is no reason Assange shouldn't face the charges brought against him by the Swedish authorities. Due process has been followed.