Make sure you download the correct 32 or 64 bit version depending on your version of libreoffice.
http://dev.mysql.com/downloads/connector/odbc/5.2.html#downloads install the odbc connector
control panel admin tools ODBC
User DSN Add Mysql ODBC......
New dialog dsn: whatever tcp/ip:
fill in the rest of the credentials Click test and make sure everything is OK.
when I launch libre office base 4.0.3 I get a database wizard What do you want to do?
Connect to an exiting database: select ODBC Browse select the ODBC you created above. connect using ODBC
username (again) check password if required
Finish Save name it whatever you want.
login again and your done