questions about myisam and innodb

this is slightly offtopic, but still if someone can shed some light on it?

these questions arose as I isntalled a plugin that states it needs atable in a DB taht has innodb as engine...

can you please help me understand innodb and myisam?
as far as I understood it, if my mysql server runs both engines, I can then make either innodb or myisam tables right? InnoDB is available on this MySQL server. or does a DB run on either one of the engines? I do not really believ this is right, but I'm not sure, jsut seeking clarification because when I create a DB there is no choice between innodb and myisam, but when I create a table I can chose the storage engine, so the table should be simple to add to the existing wp DB.