I don't really care about 'unclogging twitter' - that's for someone else to deal with, I just wanted to provide a nice group of cycling feeds, grouped together.
Voting for interesting messages is a good idea, as is adding some information in order to give some information about riders who are not Lance Armstrong and thus relatively obscure.
Seems that there are two areas to cover: who's on Twitter and what are they saying. As for who, definitely add more information but consider grouping the riders for context (by nationality, team, specialty, recent/upcoming races, etc.). Consider adding a text box to suggest another rider.
And as for what they're saying, a sort of "mute" button would be nice; Burke Swindlehurst is funny but a little too prolific. Perhaps allow the posts to be grouped by rider. That way Dave Z fans won't miss his infrequent posts, such as "Raced through a town called Bonar today..."
Though, maybe you can do some neat things with this idea.
First thing that is apparent to me is that there is too much noise. This needs to be reduced in order for me to read this feed. Maybe an up vote system (HN, reddit, etc) to stress important tweets. You could also stress the important tweets with some other metric (number of replies, number of followers, etc).
Second thing that is apparent is that I don't know who half of these cyclists are. I need to know why I am reading x person's tweets. You could expand the bio pages to include more information on the each cyclist (full name, team, rankings, wikipedia link, etc). Also, I want a list of the cyclists that are being tracked.