Do any of the elite cyclists do strength training? Or do they let their climbs develop the strength they need?
Clearly, their sport demands that they limit upper body mass. No one wants to carry extra weight up the Alps. So that has some implications for their training and diet. And I expect their legs are largely slow-twitch.
I am skeptical of Robb's assertion that strength training 2-3 times per week would be valuable to road cyclists. But I'm also quick to admit, damned if I know for sure.
Stephen Seiler's site discusses the use of strength training for rowers (power/endurance athletes). It also goes into their muscle-fiber composition. He concludes that lifting is only marginally useful for endurance athletes who clearly also need to be strong, and he also notes that Olympic rowers are slow-twitch freaks. That's probably a genetic gift, in part, and a result of adaptations from many two-a-day sessions lasting 90-120 minutes. Seiler's stuff hasn't been changed for several years, so I don't know whether recent studies would lead him to refine his thinking about strength training.
Fritz Hagerman, exercise physiologist who has worked with Olympic rowers, has noted that some elite rowers pump heroic amounts of blood through their systems, thereby powering their aerobic engines. Other rowers are uncommonly efficient at extracting oxygen from the blood that is pumped. So two different physiological mechanisms--big pump or better utilization--result in elite endurance performance in a shell. Is is reasonable to think that cyclists would also fall into one or the other of those categories? (Along with having clever doctors and pharmacists.)
I never know whether the VO2 max conversation is useful. VO2 max is genetically limited (so I've read), and it doesn't take that much specific training to reach that limit (so I've read). You want to do some VO2 specific training, because this will allow your "lactate threshold" training to occur at faster paces, but overdo the VO2 stuff, and you'll fry yourself and not be able to do the important distance training that prepares you for longer races.
Of course, if your goal is something other than being an emaciated freak, then by all means lift, but I'm not sure you'll be improving your cycling performance.
One other piece of evidence suggesting strength training is irrelevant to cyclists: the physique of Michael Rasmussen, who was leading last year's TdF before being DQ'd