I am in the process of knowing Mercurial versioning system better, and I am considering convert from SVN.
Anyone already converted? Was that difficult for you and your team
I converted. At first it was just to try it out but I have become a big fan. I didn't actually convert my personal repositories, I just exported the latest and added the files to a new Mercurial repository.
Some of the basic hg commands are similar to those in svn so that should help you start getting comfortable. Here is an explanation of the differences from Joel.
Importantly, be open to using a new process with hg. It allows much more branching and quick committing, you'll get the most out of hg if you use break out of the subversion mindset.