Nothing ventured, nothing gained. This is tough sledding and be prepared for a number of rejections. You have to position yourself so that you are doing this for them and not just yourself so that you have a better position. It has to be a win-win for both sides.
Most big events are covered by the major publications so that it is going to be an uphill battle. A good search on the event and the types of publications that may be just starting out as well might be a good approach.
I can't stress enough the fact that you have to make sure that they feel there is something in this for them. In talking to an editor a couple of years ago for a racing magazine, he said that he gets hundreds of these types of requests. While he was sympathetic to the photographers plight, he turned down most. If the event was being held in a geographic location that was too expensive for him to send his own crew he would consider a freelance photographer but he also was never comitted to using anything from them. His agreement was to pay so much per image used. At the end of the day it probably cost the freelancer money but it also got his name in print.