1) To send someone an SMS message, all you need is their SMS email address. for example, for at&t customers it's always their phone number followed by "@.att.net". then you simply send an email to that address, perhaps with php's mail() function.
2) are you in control of a unix/linux server? if so, learn about cron.
3) something that is passed thru or underneath, in order to arrive on the other side.
