Upgrading to Snow Leopard was pretty smooth save for a few items.
Sphinx was giving a little trouble connecting to mysql.
Instead of using 9.8.1, we found Sphinx 9.9-rc2 to work better.
Adding this to the config call will install the 64 bit bindings:
LDFLAGS="-arch x86_64" ./configure --prefix=/usr/local --with-mysql=/usr/local/mysql
That should take care of the mysql connection error.