You might find this article by Chris Carmichael (aka Lance's coach) helpful, I already posted it in another thread:
http://www.roadcycling.com/news/article900.shtml

Except for when you first start out, you can't easily build strength while restricting calories, you kind of have to do one or the other.

That said, last year between April and August I dropped my body fat 3% while increasing my lean body mass 2 lbs. I lifted weights three times per week and rode four times per week. I ate a balanced pescetarian ("pesco-vegetarian") diet with plenty of veggies, a decent protein source and some fat at every meal, I got a wide variety of low-gi grains, and tried to stay away from trans fat and highly refined sugar. I'm concentrating now on ramping up for the coming season, and although I'm back eating meat (though for one or fewer meals per day) I'm sticking to the same basic regimen and feeling really good about it. It looks like Nancy Clark's advice is pretty well in line with my favorite nutritional guru, Andrew Weil (http://drweil.com/).