Here's what I have, I beleive I am already doing as you suggested:
ad_page_contract {
uses bind variables in a query
@author Matthew Smith
} {
user_id:integer "1"
} -properties {
users:onerow
}
set query " select
first_name, last_name
from
ad_template_sample_users
where user_id = :user_id"
db_1row users_query $query -column_array users