Having installed MySQL for OSX from Apple’s UNIX & Open Source downloads section and Server Logistics, I found that the Perl module DBD::mysql wouldn’t compile and install. The solution it seems is to compile it by hand (oh, the horror!)

Download and unpack DBD-mysql-2.9003.tar.gz and then type the following:
cd DBD-mysql-2.9003
perl Makefile.PL –nocatchstderr
make
make test
make install
It fails a couple of parts of a test on my system, but still works ok. The –nocatchstderr option seems to be the only way to make it work.