1. upgraded from macosx 10.5 to 10.6, causing upgrade from perl 5.8.8 to 5.10.0, and therefore...
2. had to "mysqldump --database each_db_needed | gzip > each_db_needed.dump.gz
(update) 2b. Shut down running mysqld
3. had to install mysql 5.1.48 64-bit (macosc binary distro)
4. change "/usr/local/mysql" symlink target from mysql-5.0.1 to mysql-5.1.48
(update) 4b. Start mysqld
5. gunzip < each_db_needed.dump.gz | mysql 
6. set up mysql accounts and passwords
7. install DBI (standard cpan style)
8. install DBD::mysql (by hand -- for some reason, 'testuser' needed tweaking)
9. add 'export VERSIONER_PERL_PREFER_32_BIT=no' to my .bashrc
10. hope that step 9 doesn't break lots of other stuff...