Start by installing Subversion, Mercurial, and the subversion-python26bindings using macports.

sudo port install mercurial
sudo port install subversion
sudo port install subversion-python26bindings

Following the Mercurial instructions for repository importing, create a .hgrc text file in your home directory and add these lines to enable the convert extension in Mercurial:

[extensions]
hgext.convert=

Next, create an author map with the following lines to convert your unix user name to a new Mercurial user name:

johnknox=John Knox <john@fooco.com>

Then import your Subversion repository trunk into a Mecurial repository named myHg:

hg convert  --authors ~/hgUsername  file:///Users/johnknox/mySvn/myProject/trunk/ myHg

Move into the new myHg repository and updated:

cd myHg
hg update

Check that your history was properly imported:

hg log Classes/mySourceFile.m

Finally, push the repository into Kiln your empty but recently created repository:

  hg push "https://John Knox@fooco.kilnhg.com/Repo/Repositories/Group/myProject"