indexes on multiple columns

I have read the manual on indexes but i am still in the dark as to how to
construct these indexes so that I can use the fewest indexes but still have
my query make use of them. An example follows.

A table, item, has these columns among others:
id serial pk
name varchar
description text
automated boolean
available boolean
class varchar fk
subclass varchar fk

Most of the time searches will take place soley based on the id:
SELECT id FROM item WHERE id='123456';
But on occasion I might want to see info relating to a specific item and
its availability:
SELECT id FROM item WHERE name='access' AND available='true';
or just
SELECT id FROM item WHERE available='true';

If I make an index on both the name and available columns, will both the
second and third query use it?

--
Lewis Bergman
Texas Communications
4309 Maple St.
Abilene, TX 79602-8044
915-695-6962 ext 115