using matches on int4

Hi List,

I tried to do this query:
real=> select * from users where id ~ 2;
ERROR:  There is no operator '~' for types 'int4' and 'int4'
        You will either have to retype this query using an explicit cast,
        or you will have to define the operator using CREATE OPERATOR
My question is how would I create an operator?

Thanks in advance,

-Greg