need help designing a job search agent

hi all i'm trying to decide how i'm going to go about designing a monster.com-esque 'job search' agent for my job postings site. what i'm thinking is, the job search agent basically executes a sql query based on user defined parameters, then based on a set time frame, executes the sql query against a db, and emails the user the query results or generates an html summary of the query results, or both... what's the best way to set up a query/output script like this to happen automatically ala a cron job? if anyone's dealt with this type of thing before, your advice would be appreciated thanks redmond -- FreeBSD 5.1-RELEASE-p10 FreeBSD 5.1-RELEASE-p10 #0: Fri Oct 3 21:30:51 CDT 2003 3:00PM up 6 days, 6:41, 2 users, load averages: 1.00, 1.00, 1.00 VYARZERZOMANIMORORSEZASSEZANSERAREORSES?