Floyd Landis is under suspicion for doping:

Tainted at the start, the Tour de France may have been tainted at the finish, too. Floyd Landis' stunning Tour de France victory was thrown into question Thursday when his team said he tested positive for high testosterone levels during stage 17, when the 30-year-old American champion began his stunning comeback with a gritty charge into the Alps.
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Phonak said Landis would ask for an analysis of his backup sample "to prove either that this result is coming from a natural process or that this is resulting from a mistake."

I'm not terribly familiar with a lot of doping techniques... but if true, this would be a shame, and a black mark on American cycling as far as I'm concerned.  It should be noted that during stage 16, Landis bonked big time (ran out of energy).  He then had an amazing come back in stage 17.  Depending on who you are, this either proves the allegations in your mind, or it puts a bit of doubt in your mind.  When you deplete your body in the way he did, I wouldn't be surprised at all if his body naturally produced certain hormones as a reaction to it that might show up on a test.  So I'm more than willing to hear him out on this, and see what his "B" sample shows.