How can I set my upload path by date? I have a directory structure in place that I'd like to mimic in Craft. File uploads are first categorised by Year, then by month so the directory sturcture is like such

-- 2014
---- 01
---- 02
---- 03
---- 04
---- 05
---- 06


I've tried this but it still only uploads to the root folder I setup in sources

/uploads/{postDate.format('Y')}/{postDate.format('M')}


Am I using the wrong syntax? Do I need to use now | date ('Y') instead?
First you create an asset source uploads. Then you create an asset field and set its upload location subfolder to {postDate|date('Y')}/{postDate|date('m')}

When you edit an entry, any files you upload will go in the subfolder for the year and date. If you have selected Restrict uploads to a single folder? in the asset field, then only assets in that subfolder can be used.