A prompt is worth a thousand characters:
mysql> INSTALL PLUGIN postgres SONAME 'libpostgres_engine.so';
Query OK, 0 rows affected (0.02 sec)
mysql> create table april (a int , b varchar(100)) ENGINE=postgres;
Query OK, 0 rows affected (0.00 sec)
mysql> show engines;
+------------+----------+----------------------------------------------------------------+--------------+-----+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+------------+----------+----------------------------------------------------------------+--------------+-----+------------+
| ndbcluster | DISABLED | Clustered, fault-tolerant tables | YES | NO | NO |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| FEDERATED | YES | Federated MySQL storage engine | YES | NO | NO |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| InnoDB | YES | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| POSTGRES | YES | Postgres storage engine | NO | NO | NO |
| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO |
+------------+----------+----------------------------------------------------------------+--------------+-----+------------+
10 rows in set (0.00 sec)
mysql> select * from april;
Empty set (0.00 sec)
This is obviously a very early release, so you shouldn't expect much to work. It was also only made to work with Fedora Core 5, and there will be problems for other platforms.
http://download.tangent.org/postgres_engine-0.1.tar.gz