I'm trying to find out what version I currently have installed. OS X Mountain Lion (10.8.2)
Thanks in advance!
On my 10.8.3 system it's 2.2:
> ls -l /usr/lib/libxml*
-rwxr-xr-x 1 root wheel 2390032 Mar 2 17:18 /usr/lib/libxml2.2.dylib*
lrwxr-xr-x 1 root wheel 15 Mar 2 17:21 /usr/lib/libxml2.dylib@ -> libxml2.2.dylib