Tutorial : using foreign keys, retrictions etc

Hi,
       I've decided to switch from mysql to postgresql as my database server. I 
do mostly web programming (who doesnt these days?) with more than a 100 
sites developed (using mysql).
       I've read about postgresql and it's features (such as triggers, stored 
procedures, views) and I'd like to know if there is some tutorial/snippet 
of code regarding such features specially  the use of foreign keys and 
referetial integrity.
       To give a more concrete example the next app I'd like to use postgresql 
needs this behaviour :

table A
id,  name

table B
id, foo

table C
id, date
       If I change id in table A update table B to change it too (I think it's 
called cascade).
       Thanks.

- RM