[abr]

1. Yes
a) You can announce URL of statserver on your forum, MOTD message (simplest way), or with the help of some kind of advertising plugins
b) Players can use chat commands (rank, status, top20, etc.). Type "help" in chat - you'll see them in MOTD windows.
2. Start script hlstats-awards.pl daily (at midnight) by cron/sheduler

Upd.: (# 1) - Don't know if it work in HL1, sorry