Select first ten of each category?

I'm stumped on this one...

I have a table defined thusly:

create table items (
id serial,
category integer not null references category(id),
name varchar not null,
price real,
unique(category, name));

It has a LARGE number of entries. I'd like to grab the 10 most expensive items
from each category in a single query. How can this be done? Something like

Select items.*
FROM items
where id IN (
select firstTen(id) FROM items
group by category
ORDER BY price DESC
)
ORDER BY price desc;

But I've not found any incantation to make this idea work...

-Ben
--
"The best way to predict the future is to invent it."
- XEROX PARC slogan, circa 1978