Doing a conditional aggregate (e.g. count(*) if x=y) in postgres?

All;
Is there a way to get a conditional aggregate?  I have this two column view:
SELECT count(*) AS count, xx_plan.plan_name  FROM xx_membership  JOIN xx_account USING (account_id)  JOIN xx_plan USING
(plan_id)WHERE xx_membership.status = 10 GROUP BY xx_plan.plan_name;
 

And would like to add additional columns (not rows) breaking out
"status=20" and "status=30" totals.
Is this possible without a stored procedure?