how to escape _ in select

I'm trying to do this:

select * from table where field::text ilike '%\_%';

but it doesn't work.

How do you escape the _ and $ chars?

The docs say to use \, but that isn't working.

( http://www.postgresql.org/docs/8.3/static/functions-matching.html )

The text between '%...%' can be longer, I'm just trying to figure out
how to escape some things.  I've found that ' works with '' and \
works with \\

thx,

-wes