First of all go to http://www.planetminecraft.com/resources/projects/ (You have to be logged in). Under the featured projects you're going to see 'Post your project' click on it and then you'll be in this page http://www.planetminecraft.com/account/ ... /item/new/ put in the title and the rest. add some screenshots to make it more attractive. At the bottom of the page you're going to see

MCEdit Schematic:
World Download URL:
World Seed:

^ not sure if I should've used code instead of quote.. anyways. Just upload it and you're good to go.

Note: I haven't uploaded before but I think that's how you upload a map.

You're going to need a Dropbox account or a MediaFire account.

If you don't have a Dropbox account go to this link : https://www.dropbox.com/login?lhs_type=anywhere and then create an account after you create one go to this link: https://www.dropbox.com/help/19/en <-- It has a tutorial on how to upload files.

If you'd like to upload using Mediafire go to their sign up page: https://www.mediafire.com/upgrade/ and then when you're done go to this link: http://en.kioskea.net/faq/1689-uploadin ... -mediafire <--- A tutorial on how to upload files using Mediafire.