Hey - I'm trying to upload a file from my computer and am not sure how to specify the file path. I'm on a mac, running OS 10.6. Do you know how I'd link to a track say, in my user file:
It is not for the faint of heart. I strongly recommend that you use one of the client libraries that have already implemented the upload. There are client libraries listed here:
http://developer.echonest.com/pages/resources
Also note that the upload method will take a url to an mp3 file, so if your audio is on the public internet you can use the url with the upload call and avoid dealing with the multipart upload.