Hi Eric,
For non-residential buildings, the credit language is really clear: "Provide secure bicycle racks and/or storage". Bick racks are fine.
For residential, covered or indoor storage is required. It's a little more vague, but bike racks under a roof are generally considered acceptable. There is a lot more detail about this in the "Checklists" section of LEEDuser's page about this credit. And some interesting conversation in the forum area of the credit as well.