Multiple column index usage question

["Jan Muszynski" <postgres@xxxxxxxxx>]

Rather simple question, of which I'm not sure of the answer.

If I have a multiple column index, say:
    Index index1 on tableA (foo,bar)

and I then:
    Select * from "tableA" where foo = <some value>

Will index1 be used, or am I looking at a seqscan in all circumstances?

TIA
-jan m