marketing to cyclists is an amazing idea, and having bikes for loan at your inn is a fantastic ideas well. I've been into cycling since I was a teenager, and many people, myself included plan our vacations around riding. B&Bs are in a great position to welcome bikers for a few reasons:
1.Bike Storage:You can safely store people's bikes. This may not seem like a huge deal to non riders, but most riders serious enough to travel to ride probably have at least $2,000 in their bike, and that's the bottom end price wise. Have you ever attempted to store your bike securely at a hotel? It's nearly impossible and most hotels have an issue with you bringing it up the elevator and into your room. There is no way I am letting my Kona out of my site or letting some bellhop man handle it.
2.The Breakfast: It's easy to burn a silly amount of calories riding, and being able to have a real breakfast, with actual food instead of the overpriced junk at a hotel is going to make a quantifiable difference in teh quality of your ride that day. I will make one caveat that a lot of people who are traveling to a race may skip breakfast altogether.
3. The Area - many B&Bs are located in areas that have a stunning amount of trails and quiet roads. Since a lot of B&Bs are in in 'tourist' destinations there is a great likelyhood that there are maps and information available for these rides which is a big bonus.
4.The media LOVES biking stories, below is a link from a recent one I set up with MSN. If you have bike tours that involve your B&B there's a good chance someone will feature them
http://tinyurl.com/5spoza
[Links to PDF].