If you use ruby-1.9.2-p0 on Snow Leopard snailgun won’t work out of the Box!
I have included a small patch to the ruby-sources that make it work:
(this is assuming you use rvm)
cd $HOME/.rvm/src/ruby-1.9.2-p0/ext/socket patch -p1 < wherever_snailgun_was_installed/ruby-1.9.2-p0.patch ruby extconf.rb make clean make clean install
Patch was taken from redmine.ruby-lang.org/repositories/revision/ruby-19?rev=29242
[email protected] 20101024