Not necessarily all the details, but at least the very basic story should be available through CNN:
http://www.cnn.com/US/9810/13/gay.mock.float/
At the time this was widely disseminated international news.
The Pi Kappa Alpha chapter was closed or suspended for a few years. Almost immediately after the story broke, the Alpha Chi Omega chapter members voted to return their charter. (I have read that the sorority members were essentially given a choice by their national officers: vote to return their charter ASAP, or their charter would be revoked by Alpha Chi Omega.)
Lots of news and views on the incident can be found with an ordinary Google web search on some combination of words like ---
colorado state parade float alpha kappa omega
-- or whatever combination of words might seem reasonable . . . scarecrow might be another word you could throw into the search mix.