Using a different MySQL database engine

I am having problems trying to use a different MySQL database engine. (I want to change from MyISAM to InnoDB)

/etc/my.cnf

[mysqld]
bind-address = 127.0.0.1
default-storage-engine=InnoDB

It appears that it is not installed? If that is true, how can I install InnoDB?

mysql> show engines;
+开发者_如何学JAVA------------+---------+-----------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                   | Transactions | XA   | Savepoints |
+------------+---------+-----------------------------------------------------------+--------------+------+------------+
| CSV        | YES     | CSV storage engine                                        | NO           | NO   | NO         | 
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                     | NO           | NO   | NO         | 
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables | NO           | NO   | NO         | 
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance    | NO           | NO   | NO         | 
+------------+---------+-----------------------------------------------------------+--------------+------+------------+
4 rows in set (0.00 sec)

I am on Mac OS 10.5 and I am using MySQL version 5.1.35.

See here

http://dev.mysql.com/doc/refman/5.1/en/pluggable-storage.html

You'll need to locate download the appropriate build of the InnoDB plugin.