First, realize that your boss can say 'no'. That being said, there are a couple of ways to go about this. If this is a small company, and your boss is 'The Boss', then just professionally tell him that a company you know is interested in a website. As a small business owner (with an employee of 1, but whatever) I would appreciate if someone came to me with potential business, employee or not. If your boss is not the 'approachable type', don't make small talk and just cut straight to the point. I recommend not to make small talk anyway to avoid beating around the bush, but that is even more of a reason not to.
If this is a bigger company, or if the company has a 'sales department', then take it to them. If you know someone in that department that could get it handled, let them know and commit yourself to follow up to see what's happening with the request, no reason to let the potential business go down the drain.
Lastly, if it falls through with the company you work for, take up the job on your own if you have time. I would have suggested this first but it wasn't your question. If you don't have the skill, maybe there are trusty coworkers you could work with on the project. Be careful if you go down this route, it could be seen as stealing your company's business if you didn't ask them first, which could be grounds for dismissal.
And if you don't want to touch it at all you could always give them my contact info :-)