I can’t post links but you can google the verbiage here to find the various archived pages.
Start of the contest:
We’re looking for the greatest of heroes to step forward and demonstrate their skill and valor. If you can prove your worth by becoming the most powerful members of your faction classes, then you could win the chance to continue your adventures in Azeroth beyond the completion of the stress test!
Blizzard will be holding a competition during the stress test to determine the three highest-level characters per class in both the Alliance and Horde factions. At the end of the stress test, three players of every Horde class and three players of every Alliance class will win entry into the World of Warcraft closed beta test. In the event of a tie, total experience accumulated will determine the ultimate winners.
In the interest of fairness and in accordance with the World of Warcraft Beta Test Agreement and Terms of Use Agreement, players are not allowed to share accounts. Any character that has been leveled up through shared playtime by multiple players will be disqualified from the contest.
The competition will run through the entire duration of the stress test. At the end of the stress test, Blizzard will notify 48 lucky winners of their acceptance into the closed beta test.
Conclusion of the contest:
In September, Blizzard held a stress test beta for World of Warcraft to help tune the game’s network infrastructure. Over 100,000 participants signed up for the stress test beta and connected to our servers to help us analyze performance under heavy loads. In conjunction with that, we ran a small contest as a means of allowing a large selection of dedicated stress testers to continue on into the closed beta test. The 720 players listed represent the winning stress testers. These characters achieved the highest level of experience for their race and class, per faction, on the server on which they were created. Congratulations!
Blizzard has gotten around to posting the contest results for all to see. Congratulations to all who won and welcome to the World of Warcraft Beta Test!
As for the timeframe, you can use some context on a forum post:
Yeah it was nice, didn’t played in the last 3 days tho, never got a char above level 10 !
And finally a post of them “extending it to Sunday” on Sept 9th, 2004 which was a Thursday:
We are extending the stress test beta to this Sunday and adding thousands of additional testers from the group of gamers that are currently on the closed-beta waiting list. Invitation emails have started going out to the new testers already. The stress test beta contest will continue on until the end of the stress test beta, at which time all stress test accounts will expire.
Please do not contact Blizzard to inquire about being added to the stress test beta; all the information needed, such as how to access the stress test beta, will be provided in the email going out to new testers.
Thanks to the stress testers, the development team has gained a great deal of information that is proving to be extremely valuable in the development of World of Warcraft. By extending the stress test beta, we will be able to gather even more useful data, which will help us ensure a smooth launch for World of Warcraft later this year. Thanks again, and we’ll see you online!