on-line athletic training log

I need to build an on-line training log where a coach can enter training routines for specific athletes and atheltes can retrieve their training and log their daily results. Has anyone ever done/started a project along these line? Has anyone seen somethign like this done in PHP? Has anyone seen something similar that could be hacked up and altered to suit my needs? Just figured I'd ask around before I do this from scratch and "re-invent the wheel"... -Brian